diff --git a/virtcontainers/agent.go b/virtcontainers/agent.go
index f5ada6ada6..954a79955c 100644
--- a/virtcontainers/agent.go
+++ b/virtcontainers/agent.go
@@ -207,7 +207,8 @@ type agent interface {
 	// onlineCPUMem will online CPUs and Memory inside the Sandbox.
 	// This function should be called after hot adding vCPUs or Memory.
 	// cpus specifies the number of CPUs that were added and the agent should online
-	onlineCPUMem(cpus uint32) error
+	// cpuOnly specifies that we should online cpu or online memory or both
+	onlineCPUMem(cpus uint32, cpuOnly bool) error
 
 	// statsContainer will tell the agent to get stats from a container related to a Sandbox
 	statsContainer(sandbox *Sandbox, c Container) (*ContainerStats, error)
diff --git a/virtcontainers/api_test.go b/virtcontainers/api_test.go
index 830b1fd5c2..5dc6e422ca 100644
--- a/virtcontainers/api_test.go
+++ b/virtcontainers/api_test.go
@@ -2330,12 +2330,18 @@ func TestUpdateContainer(t *testing.T) {
 
 	period := uint64(1000)
 	quota := int64(2000)
+	memoryLimit := int64(1073741824)
+	memorySwap := int64(1073741824)
 	assert := assert.New(t)
 	resources := specs.LinuxResources{
 		CPU: &specs.LinuxCPU{
 			Period: &period,
 			Quota:  &quota,
 		},
+		Memory: &specs.LinuxMemory{
+			Limit: &memoryLimit,
+			Swap:  &memorySwap,
+		},
 	}
 	err := UpdateContainer(ctx, "", "", resources)
 	assert.Error(err)
diff --git a/virtcontainers/container.go b/virtcontainers/container.go
index a54e493419..073b41da65 100644
--- a/virtcontainers/container.go
+++ b/virtcontainers/container.go
@@ -11,6 +11,7 @@ import (
 	"encoding/hex"
 	"fmt"
 	"io"
+	"math"
 	"os"
 	"path/filepath"
 	"syscall"
@@ -177,7 +178,7 @@ type ContainerResources struct {
 	VCPUs uint32
 
 	// Mem is the memory that is being used by the container
-	Mem uint32
+	MemMB uint32
 }
 
 // ContainerConfig describes one container runtime configuration.
@@ -991,6 +992,7 @@ func (c *Container) update(resources specs.LinuxResources) error {
 
 	newResources := ContainerResources{
 		VCPUs: uint32(utils.ConstraintsToVCPUs(*resources.CPU.Quota, *resources.CPU.Period)),
+		MemMB: uint32(*resources.Memory.Limit >> 20),
 	}
 
 	if err := c.updateResources(currentConfig.Resources, newResources); err != nil {
@@ -1216,7 +1218,7 @@ func (c *Container) addResources() error {
 			}
 		}
 
-		return c.sandbox.agent.onlineCPUMem(vcpusAdded)
+		return c.sandbox.agent.onlineCPUMem(vcpusAdded, true)
 	}
 
 	return nil
@@ -1247,16 +1249,14 @@ func (c *Container) removeResources() error {
 	return nil
 }
 
-func (c *Container) updateResources(oldResources, newResources ContainerResources) error {
-	//TODO add support for memory, Issue: https://github.com/containers/virtcontainers/issues/578
+func (c *Container) updateVCPUResources(oldResources, newResources ContainerResources) error {
 	var vCPUs uint32
 	oldVCPUs := oldResources.VCPUs
 	newVCPUs := newResources.VCPUs
 
-	// Update vCPUs is not possible if period and/or quota are not set or
-	// oldVCPUs and newVCPUs are equal.
+	// Update vCPUs is not possible if oldVCPUs and newVCPUs are equal.
 	// Don't fail, the constraint still can be applied in the cgroup.
-	if newVCPUs == 0 || oldVCPUs == newVCPUs {
+	if oldVCPUs == newVCPUs {
 		c.Logger().WithFields(logrus.Fields{
 			"old-vcpus": fmt.Sprintf("%d", oldVCPUs),
 			"new-vcpus": fmt.Sprintf("%d", newVCPUs),
@@ -1278,7 +1278,7 @@ func (c *Container) updateResources(oldResources, newResources ContainerResource
 		}
 		// recalculate the actual number of vCPUs if a different number of vCPUs was added
 		newResources.VCPUs = oldVCPUs + vcpusAdded
-		if err := c.sandbox.agent.onlineCPUMem(vcpusAdded); err != nil {
+		if err := c.sandbox.agent.onlineCPUMem(vcpusAdded, true); err != nil {
 			return err
 		}
 	} else {
@@ -1296,8 +1296,82 @@ func (c *Container) updateResources(oldResources, newResources ContainerResource
 		// recalculate the actual number of vCPUs if a different number of vCPUs was removed
 		newResources.VCPUs = oldVCPUs - vcpusRemoved
 	}
-
-	// Set and save container's config
-	c.config.Resources = newResources
-	return c.storeContainer()
+	return nil
+}
+
+func (c *Container) memHotplugValid(mem *uint32) error {
+	// TODO: make memory aligned to correct memory boundary according to different architecture
+	const memorySectionSizeMB = 128
+	// TODO: make hot add memory to be aligned to memory section in more proper way. See https://github.com/kata-containers/runtime/pull/624#issuecomment-419656853
+	*mem = uint32(math.Ceil(float64(*mem)/memorySectionSizeMB)) * memorySectionSizeMB
+
+	return nil
+}
+
+func (c *Container) updateMemoryResources(oldResources, newResources ContainerResources) error {
+	oldMemMB := oldResources.MemMB
+	newMemMB := newResources.MemMB
+
+	if oldMemMB == newMemMB {
+		c.Logger().WithFields(logrus.Fields{
+			"old-mem": fmt.Sprintf("%dMB", oldMemMB),
+			"new-mem": fmt.Sprintf("%dMB", newMemMB),
+		}).Debug("the actual number of Mem will not be modified")
+		return nil
+	}
+
+	if oldMemMB < newMemMB {
+		// hot add memory
+		addMemMB := newMemMB - oldMemMB
+		if err := c.memHotplugValid(&addMemMB); err != nil {
+			return err
+		}
+
+		virtLog.Debugf("hot adding %dMB mem", addMemMB)
+		addMemDevice := &memoryDevice{
+			sizeMB: int(addMemMB),
+		}
+		_, err := c.sandbox.hypervisor.hotplugAddDevice(addMemDevice, memoryDev)
+		if err != nil {
+			return err
+		}
+		newResources.MemMB = newMemMB
+		if err := c.sandbox.agent.onlineCPUMem(0, false); err != nil {
+			return err
+		}
+	}
+	// hot remove memory unsupported
+	return nil
+}
+
+func (c *Container) updateResources(oldResources, newResources ContainerResources) error {
+	// initialize with oldResources
+	c.config.Resources.VCPUs = oldResources.VCPUs
+	c.config.Resources.MemMB = oldResources.MemMB
+
+	// Cpu is not updated if period and/or quota not set
+	if newResources.VCPUs != 0 {
+		if err := c.updateVCPUResources(oldResources, newResources); err != nil {
+			return err
+		}
+
+		// Set and save container's config VCPUs field only
+		c.config.Resources.VCPUs = newResources.VCPUs
+		if err := c.storeContainer(); err != nil {
+			return err
+		}
+	}
+
+	// Memory is not updated if memory limit not set
+	if newResources.MemMB != 0 {
+		if err := c.updateMemoryResources(oldResources, newResources); err != nil {
+			return err
+		}
+
+		// Set and save container's config MemMB field only
+		c.config.Resources.MemMB = newResources.MemMB
+		return c.storeContainer()
+	}
+
+	return nil
 }
diff --git a/virtcontainers/hyperstart_agent.go b/virtcontainers/hyperstart_agent.go
index 35d7964200..2e36faa1a1 100644
--- a/virtcontainers/hyperstart_agent.go
+++ b/virtcontainers/hyperstart_agent.go
@@ -883,7 +883,7 @@ func (h *hyper) sendCmd(proxyCmd hyperstartProxyCmd) (interface{}, error) {
 	return h.client.HyperWithTokens(proxyCmd.cmd, tokens, proxyCmd.message)
 }
 
-func (h *hyper) onlineCPUMem(cpus uint32) error {
+func (h *hyper) onlineCPUMem(cpus uint32, cpuOnly bool) error {
 	// hyperstart-agent uses udev to online CPUs automatically
 	return nil
 }
diff --git a/virtcontainers/kata_agent.go b/virtcontainers/kata_agent.go
index 3581fd01f8..54d79df223 100644
--- a/virtcontainers/kata_agent.go
+++ b/virtcontainers/kata_agent.go
@@ -1234,10 +1234,11 @@ func (k *kataAgent) resumeContainer(sandbox *Sandbox, c Container) error {
 	return err
 }
 
-func (k *kataAgent) onlineCPUMem(cpus uint32) error {
+func (k *kataAgent) onlineCPUMem(cpus uint32, cpuOnly bool) error {
 	req := &grpc.OnlineCPUMemRequest{
-		Wait:   false,
-		NbCpus: cpus,
+		Wait:    false,
+		NbCpus:  cpus,
+		CpuOnly: cpuOnly,
 	}
 
 	_, err := k.sendReq(req)
diff --git a/virtcontainers/kata_agent_test.go b/virtcontainers/kata_agent_test.go
index 8f884285c1..7c8c762e09 100644
--- a/virtcontainers/kata_agent_test.go
+++ b/virtcontainers/kata_agent_test.go
@@ -317,7 +317,7 @@ func TestKataAgentSendReq(t *testing.T) {
 	err = k.resumeContainer(sandbox, Container{})
 	assert.Nil(err)
 
-	err = k.onlineCPUMem(1)
+	err = k.onlineCPUMem(1, true)
 	assert.Nil(err)
 
 	_, err = k.statsContainer(sandbox, Container{})
diff --git a/virtcontainers/noop_agent.go b/virtcontainers/noop_agent.go
index e98bcd74fe..7294198865 100644
--- a/virtcontainers/noop_agent.go
+++ b/virtcontainers/noop_agent.go
@@ -94,7 +94,7 @@ func (n *noopAgent) updateContainer(sandbox *Sandbox, c Container, resources spe
 }
 
 // onlineCPUMem is the Noop agent Container online CPU and Memory implementation. It does nothing.
-func (n *noopAgent) onlineCPUMem(cpus uint32) error {
+func (n *noopAgent) onlineCPUMem(cpus uint32, cpuOnly bool) error {
 	return nil
 }
 
diff --git a/virtcontainers/pkg/oci/utils.go b/virtcontainers/pkg/oci/utils.go
index 665b541239..f9f97fb172 100644
--- a/virtcontainers/pkg/oci/utils.go
+++ b/virtcontainers/pkg/oci/utils.go
@@ -566,6 +566,11 @@ func ContainerConfig(ocispec CompatOCISpec, bundlePath, cid, console string, det
 			resources.VCPUs = uint32(utils.ConstraintsToVCPUs(*ocispec.Linux.Resources.CPU.Quota, *ocispec.Linux.Resources.CPU.Period))
 		}
 	}
+	if ocispec.Linux.Resources.Memory != nil {
+		if ocispec.Linux.Resources.Memory.Limit != nil {
+			resources.MemMB = uint32(*ocispec.Linux.Resources.Memory.Limit >> 20)
+		}
+	}
 
 	containerConfig := vc.ContainerConfig{
 		ID:             cid,
diff --git a/virtcontainers/qemu.go b/virtcontainers/qemu.go
index f33f436086..337cc68b8a 100644
--- a/virtcontainers/qemu.go
+++ b/virtcontainers/qemu.go
@@ -1044,6 +1044,11 @@ func (q *qemu) hotplugMemory(memDev *memoryDevice, op operation) error {
 		return errors.New("cannot hot unplug memory device")
 	}
 
+	err := q.qmpSetup()
+	if err != nil {
+		return err
+	}
+
 	maxMem, err := q.hostMemMB()
 	if err != nil {
 		return err
@@ -1058,16 +1063,20 @@ func (q *qemu) hotplugMemory(memDev *memoryDevice, op operation) error {
 			memDev.sizeMB, currentMemory, q.config.MemorySize)
 	}
 
+	memoryDevices, err := q.qmpMonitorCh.qmp.ExecQueryMemoryDevices(q.qmpMonitorCh.ctx)
+	if err != nil {
+		return fmt.Errorf("failed to query memory devices: %v", err)
+	}
+
+	if len(memoryDevices) != 0 {
+		memDev.slot = memoryDevices[len(memoryDevices)-1].Data.Slot + 1
+	}
+
 	return q.hotplugAddMemory(memDev)
 }
 
 func (q *qemu) hotplugAddMemory(memDev *memoryDevice) error {
-	err := q.qmpSetup()
-	if err != nil {
-		return err
-	}
-
-	err = q.qmpMonitorCh.qmp.ExecHotplugMemory(q.qmpMonitorCh.ctx, "memory-backend-ram", "mem"+strconv.Itoa(memDev.slot), "", memDev.sizeMB)
+	err := q.qmpMonitorCh.qmp.ExecHotplugMemory(q.qmpMonitorCh.ctx, "memory-backend-ram", "mem"+strconv.Itoa(memDev.slot), "", memDev.sizeMB)
 	if err != nil {
 		q.Logger().WithError(err).Error("hotplug memory")
 		return err
diff --git a/virtcontainers/vm.go b/virtcontainers/vm.go
index dd3dc67a31..534a78c5af 100644
--- a/virtcontainers/vm.go
+++ b/virtcontainers/vm.go
@@ -268,7 +268,7 @@ func (v *VM) AddMemory(numMB uint32) error {
 // OnlineCPUMemory puts the hotplugged CPU and memory online.
 func (v *VM) OnlineCPUMemory() error {
 	v.logger().Infof("online CPU %d and memory", v.cpuDelta)
-	err := v.agent.onlineCPUMem(v.cpuDelta)
+	err := v.agent.onlineCPUMem(v.cpuDelta, false)
 	if err == nil {
 		v.cpuDelta = 0
 	}