diff --git a/configure.in b/configure.in
index 4700a24..68b805b 100644
--- a/configure.in
+++ b/configure.in
@@ -5,12 +5,29 @@ AC_CONFIG_MACRO_DIR([m4])
 AM_INIT_AUTOMAKE([subdir-objects])
 AM_MAINTAINER_MODE([disable])

+AC_MSG_CHECKING([if debug build is enabled])
+
+AC_ARG_ENABLE([debug],
+        [AC_HELP_STRING([--enable-debug],
+            [Enable debug build. [default=no]])],
+        [enable_debug=yes],
+        [enable_debug=no]
+        )
+
+AC_MSG_RESULT([$enable_debug])
+
+if test "$enable_debug" = yes; then
+    OPT_FLAGS="-O0 -g"
+else
+    OPT_FLAGS="-O3"
+fi
+
 if test -z "$CFLAGS"; then
-    CFLAGS="-O3"
+    CFLAGS="$OPT_FLAGS"
 fi

 if test -z "$CXXFLAGS"; then
-    CXXFLAGS="-O3"
+    CXXFLAGS="$OPT_FLAGS"
 fi

 AM_CONFIG_HEADER([src/config/config.h])