diff --git a/plugins/outputs/mqtt/README.md b/plugins/outputs/mqtt/README.md
index aa028e056..abb770f06 100644
--- a/plugins/outputs/mqtt/README.md
+++ b/plugins/outputs/mqtt/README.md
@@ -59,5 +59,6 @@ This plugin writes to a [MQTT Broker](http://http://mqtt.org/) acting as a mqtt
 * `tls_cert`: TLS CERT
 * `tls_key`: TLS key
 * `insecure_skip_verify`: Use TLS but skip chain & host verification (default: false)
+* `batch`: When true, metrics will be sent in one MQTT message per flush. Otherwise, metrics are written one metric per MQTT message.
 * `retain`: Set `retain` flag when publishing
 * `data_format`: [About Telegraf data formats](https://github.com/influxdata/telegraf/blob/master/docs/DATA_FORMATS_OUTPUT.md)