diff --git a/clients/c/cosmopolite.c b/clients/c/cosmopolite.c
index b7a9568..120d927 100644
--- a/clients/c/cosmopolite.c
+++ b/clients/c/cosmopolite.c
@@ -254,6 +254,18 @@ void cosmo_subscribe(cosmo *instance, const json_t *subject, const json_int_t me
   cosmo_send_command(instance, cosmo_command("subscribe", arguments));
 }
 
+void cosmo_send_message(cosmo *instance, const json_t *subject, json_t *message) {
+  char sender_message_id[COSMO_UUID_SIZE];
+  cosmo_generate_uuid(sender_message_id);
+  char *encoded = json_dumps(message, JSON_ENCODE_ANY);
+  json_t *arguments = json_pack("{sOssss}",
+      "subject", subject,
+      "message", encoded,
+      "sender_message_id", sender_message_id);
+  cosmo_send_command(instance, cosmo_command("sendMessage", arguments));
+  free(encoded);
+}
+
 cosmo *cosmo_create(const char *base_url, const char *client_id) {
   curl_global_init(CURL_GLOBAL_DEFAULT);
   srandomdev();
diff --git a/clients/c/cosmopolite.h b/clients/c/cosmopolite.h
index 6b49ee8..599f076 100644
--- a/clients/c/cosmopolite.h
+++ b/clients/c/cosmopolite.h
@@ -29,5 +29,6 @@ void cosmo_destroy(cosmo *instance);
 
 json_t *cosmo_subject(const char *name, const char *readable_only_by, const char *writeable_only_by);
 void cosmo_subscribe(cosmo *instance, const json_t *subject, const json_int_t messages, const json_int_t last_id);
+void cosmo_send_message(cosmo *instance, const json_t *subject, json_t *message);
 
 #endif
diff --git a/clients/c/test.c b/clients/c/test.c
index 1bce181..f8ddf76 100644
--- a/clients/c/test.c
+++ b/clients/c/test.c
@@ -8,6 +8,9 @@ int main(int argc, char *argv[]) {
   cosmo *instance = cosmo_create("https://playground.cosmopolite.org/cosmopolite", client_id);
   json_t *subject = cosmo_subject("foobar", NULL, NULL);
   cosmo_subscribe(instance, subject, -1, 0);
+  json_t *message = json_string("test from C");
+  cosmo_send_message(instance, subject, message);
+  json_decref(message);
   json_decref(subject);
   sleep(120);
   cosmo_destroy(instance);