diff --git a/gst-libs/gst/base/Makefile.am b/gst-libs/gst/base/Makefile.am
index 7273e21560..5f3dc1f38a 100644
--- a/gst-libs/gst/base/Makefile.am
+++ b/gst-libs/gst/base/Makefile.am
@@ -3,7 +3,9 @@ lib_LTLIBRARIES = libgstbadbase-@GST_API_VERSION@.la
 libgstbadbase_@GST_API_VERSION@_la_SOURCES = \
 	gstaggregator.c
 
-libgstbadbase_@GST_API_VERSION@_la_CFLAGS = $(GST_CFLAGS)
+libgstbadbase_@GST_API_VERSION@_la_CFLAGS = $(GST_CFLAGS) \
+	-DGST_USE_UNSTABLE_API
+
 libgstbadbase_@GST_API_VERSION@_la_LIBADD = $(GST_LIBS)
 libgstbadbase_@GST_API_VERSION@_la_LDFLAGS = $(GST_LDFLAGS)
 
diff --git a/gst-libs/gst/base/gstaggregator.h b/gst-libs/gst/base/gstaggregator.h
index 3965ccc48f..507da136cb 100644
--- a/gst-libs/gst/base/gstaggregator.h
+++ b/gst-libs/gst/base/gstaggregator.h
@@ -23,6 +23,11 @@
 #ifndef __GST_AGGREGATOR_H__
 #define __GST_AGGREGATOR_H__
 
+#ifndef GST_USE_UNSTABLE_API
+#warning "The Base library from gst-plugins-bad is unstable API and may change in future."
+#warning "You can define GST_USE_UNSTABLE_API to avoid this warning."
+#endif
+
 #include <gst/gst.h>
 
 G_BEGIN_DECLS