diff --git a/plugins/inputs/snmp/README.md b/plugins/inputs/snmp/README.md
index dab28e9b0a976..a33715f075e1e 100644
--- a/plugins/inputs/snmp/README.md
+++ b/plugins/inputs/snmp/README.md
@@ -98,7 +98,7 @@ Resulting output:
 ### Config parameters
 
 * `agents`: Default: `[]`
-List of SNMP agents to connect to in the form of `IP[:PORT]`. If `:PORT` is unspecified, it defaults to `161`.
+List of SNMP agents to connect to in the form of `[tcp:]IP[:PORT]`. If `:PORT` is unspecified, it defaults to `161`. When using the optional prefix `tcp:`, SNMP over TCP will be used. Otherwise UDP is used as the transport protocol.
 
 * `version`: Default: `2`
 SNMP protocol version to use.