diff --git a/src/pulsecore/tagstruct.c b/src/pulsecore/tagstruct.c
index 8a29957b4..50168717f 100644
--- a/src/pulsecore/tagstruct.c
+++ b/src/pulsecore/tagstruct.c
@@ -310,7 +310,7 @@ void pa_tagstruct_put_volume(pa_tagstruct *t, pa_volume_t vol) {
     write_u32(t, vol);
 }
 
-void pa_tagstruct_put_proplist(pa_tagstruct *t, pa_proplist *p) {
+void pa_tagstruct_put_proplist(pa_tagstruct *t, const pa_proplist *p) {
     void *state = NULL;
     pa_assert(t);
     pa_assert(p);
diff --git a/src/pulsecore/tagstruct.h b/src/pulsecore/tagstruct.h
index 348c65d2d..9236490ad 100644
--- a/src/pulsecore/tagstruct.h
+++ b/src/pulsecore/tagstruct.h
@@ -81,7 +81,7 @@ void pa_tagstruct_put_timeval(pa_tagstruct*t, const struct timeval *tv);
 void pa_tagstruct_put_usec(pa_tagstruct*t, pa_usec_t u);
 void pa_tagstruct_put_channel_map(pa_tagstruct *t, const pa_channel_map *map);
 void pa_tagstruct_put_cvolume(pa_tagstruct *t, const pa_cvolume *cvolume);
-void pa_tagstruct_put_proplist(pa_tagstruct *t, pa_proplist *p);
+void pa_tagstruct_put_proplist(pa_tagstruct *t, const pa_proplist *p);
 void pa_tagstruct_put_volume(pa_tagstruct *t, pa_volume_t volume);
 void pa_tagstruct_put_format_info(pa_tagstruct *t, pa_format_info *f);