diff --git a/samples/psk/client.lua b/samples/psk/client.lua
index 75eeb63..0308463 100644
--- a/samples/psk/client.lua
+++ b/samples/psk/client.lua
@@ -4,6 +4,11 @@
 local socket = require("socket")
 local ssl    = require("ssl")
 
+if not ssl.config.capabilities.psk then
+   print("[ERRO] PSK not available")
+   os.exit(1)
+end
+
 -- @param hint (nil | string)
 -- @param max_identity_len (number)
 -- @param max_psk_len (number)
diff --git a/samples/psk/server.lua b/samples/psk/server.lua
index b5a958b..1f19d9f 100644
--- a/samples/psk/server.lua
+++ b/samples/psk/server.lua
@@ -4,6 +4,11 @@
 local socket = require("socket")
 local ssl    = require("ssl")
 
+if not ssl.config.capabilities.psk then
+   print("[ERRO] PSK not available")
+   os.exit(1)
+end
+
 -- @param identity (string)
 -- @param max_psk_len (number)
 -- @return psk (string)