diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index b6e8a1d..ec23c8a 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -201,8 +201,12 @@
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
-#define USAGE_PSK                                                   \
-    "    psk=%%s              default: \"\" (in hex, without 0x)\n" \
+#define USAGE_PSK                                                       \
+    "    psk=%%s              default: \"\" (in hex, without 0x)\n"     \
+    "    psk_list=%%s         default: \"\"\n"                          \
+    "                          A list of (PSK identity, PSK value) pairs.\n" \
+    "                          The PSK values are in hex, without 0x.\n" \
+    "                          id1,psk1[,id2,psk2[,...]]\n"             \
     "    psk_identity=%%s     default: \"Client_identity\"\n"
 #else
 #define USAGE_PSK ""