diff --git a/Makefile.defs b/Makefile.defs
index 09b37521..d2671f49 100644
--- a/Makefile.defs
+++ b/Makefile.defs
@@ -36,7 +36,7 @@ CPPFLAGS += -D_DEBUG \
 
 #
 # ZRTP support? (see zfoneproject.com)
-#WITH_ZRTP = yes
+WITH_ZRTP = yes
 
 #
 # exclude some modules from compilation?
@@ -91,6 +91,13 @@ ifeq ($(DEBUG_PLAYOUT), yes)
 CPPFLAGS +=  -DDEBUG_PLAYOUTBUF
 endif
 
+ifdef WITH_ZRTP
+CPPFLAGS += -DWITH_ZRTP \
+	    -DBUILD_ZRTP_MUTEXES \
+	    -DBUILD_DEFAULT_CACHE -DBUILD_DEFAULT_TIMER -DUNIX -DBUILD_ZRTP_MUTEXES \
+	    -I/usr/local/include/zrtp 
+endif
+
 TARGET =
 LIB_LDFLAGS = -shared
 
diff --git a/core/Makefile b/core/Makefile
index eacd2665..f153a4f7 100644
--- a/core/Makefile
+++ b/core/Makefile
@@ -66,10 +66,6 @@ LDFLAGS +=-lsamplerate
 endif
 
 ifdef WITH_ZRTP
-CPPFLAGS += -DWITH_ZRTP \
-	    -DBUILD_ZRTP_MUTEXES \
-	    -DBUILD_DEFAULT_CACHE -DBUILD_DEFAULT_TIMER -DUNIX -DBUILD_ZRTP_MUTEXES \
-	    -I/usr/local/include/zrtp 
 LDFLAGS +=-lzrtp -lbn
 endif