--- a/setup.py
+++ b/setup.py
@@ -95,7 +95,7 @@
 library_dirs = [get_python_lib(), pg_config('libdir')]
 define_macros = [('PYGRESQL_VERSION', version)]
 undef_macros = []
-extra_compile_args = ['-O2', '-funsigned-char', '-Wall', '-Wconversion']
+extra_compile_args = ['-funsigned-char', '-Wall']
 
 
 class build_pg_ext(build_ext):