diff --git a/CMakeLists.txt b/CMakeLists.txt
index d5c5456189..f92e80f977 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -69,13 +69,13 @@ option(ARMA_EXTRA_DEBUG "Compile with extra Armadillo debugging symbols." OFF)
 
 if(DEBUG)
   add_definitions(-DDEBUG)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -Wall -O0")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99 -g -Wall -O0")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -Wall -O0 -Wextra -Werror")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99 -g -Wall -Wextra -Werror -O0")
 else()
   add_definitions(-DARMA_NO_DEBUG)
   add_definitions(-DNDEBUG)
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -O2")
-  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99 -Wall -O2")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra -Werror -O2")
+  set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c99 -Wall -Wextra -Werror -O2")
 endif(DEBUG)
 
 if(PROFILE)