diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0acd26f..218c48b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -61,7 +61,6 @@ if(NOT LIBDEFLATE_BUILD_STATIC_LIB)
 endif()
 
 # Set common C compiler flags for all targets (the library and the programs).
-set(CMAKE_C_FLAGS_RELEASE "-O2 -DNDEBUG")
 set(CMAKE_C_STANDARD 99)
 if(NOT MSVC)
     check_c_compiler_flag(-Wdeclaration-after-statement HAVE_WDECLARATION_AFTER_STATEMENT)