diff --git a/clients/c/cosmopolite.h b/clients/c/cosmopolite.h
index b759e67..b1b9071 100644
--- a/clients/c/cosmopolite.h
+++ b/clients/c/cosmopolite.h
@@ -5,6 +5,7 @@
 #include <jansson.h>
 #include <pthread.h>
 #include <stdbool.h>
+#include <stdint.h>
 
 #define COSMO_UUID_SIZE 37