diff --git a/docs/INSTALL b/docs/INSTALL
index e08b9581c4d5f1c1f1db022553a29ee7602a365b..4a6f4140191063eb6508e1e06ed1f5b65291fbe9 100644
--- a/docs/INSTALL
+++ b/docs/INSTALL
@@ -307,6 +307,7 @@ Win32
    CURL_DISABLE_TELNET   disables TELNET
    CURL_DISABLE_DICT     disables DICT
    CURL_DISABLE_FILE     disables FILE
+   CURL_DISABLE_TFTP     disables TFTP
 
    If you want to set any of these defines you have the following
    possibilities: