diff --git a/src/Makefile.am b/src/Makefile.am
index a0781a3..6f58a9a 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,7 +1,11 @@
 AUTOMAKE_OPTIONS = subdir-objects
 
 if DEBUG
-AM_CPPFLAGS = -DDEBUG
+    AM_CFLAGS = -g3 -O0 -DDEBUG
+    AM_CXXFLAGS = -g3 -O0 -DDEBUG
+else
+    AM_CFLAGS = -O2
+    AM_CXXFLAGS = -O2
 endif
 
 lib_LTLIBRARIES = libuldaq.la