diff --git a/.travis.yml b/.travis.yml
index f0678351..7655a564 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -32,7 +32,7 @@ script:
     - cd ..
     - mkdir build
     - cd build
-    - cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE
+    - cmake .. -DCMAKE_BUILD_TYPE=$BUILD_TYPE -DDRAIOS_DEBUG_FLAGS="-D_DEBUG -DNDEBUG"
     - make VERBOSE=1
     - make package
     - cd ..
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5d54005c..b9fc30fa 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,9 @@ if(NOT CMAKE_BUILD_TYPE)
 	SET(CMAKE_BUILD_TYPE Release)
 endif()
 
-set(DRAIOS_DEBUG_FLAGS "-D_DEBUG")
+if(NOT DRAIOS_DEBUG_FLAGS)
+	set(DRAIOS_DEBUG_FLAGS "-D_DEBUG")
+endif()
 
 set(CMAKE_C_FLAGS "-Wall -ggdb ${DRAIOS_FEATURE_FLAGS}")
 set(CMAKE_CXX_FLAGS "-Wall -ggdb --std=c++0x ${DRAIOS_FEATURE_FLAGS}")