diff --git a/include/mbedtls/oid.h b/include/mbedtls/oid.h
index fcecdaf..618c0ea 100644
--- a/include/mbedtls/oid.h
+++ b/include/mbedtls/oid.h
@@ -282,6 +282,8 @@
 
 /*
  * ECParameters namedCurve identifiers, from RFC 5480, RFC 5639, and SEC2
+ * When adding new OID's, please update \c MBEDTLS_ECP_GRP_OID_MAX_SIZE
+ * in ecp.h
  */
 
 /* secp192r1 OBJECT IDENTIFIER ::= {