diff --git a/man/foreman.1 b/man/foreman.1
index af76a0d..19f4c1d 100644
--- a/man/foreman.1
+++ b/man/foreman.1
@@ -132,7 +132,7 @@ job: bundle exec rake jobs:work
 .IP "" 0
 .
 .P
-You can validate your Procfile format using the \fBcheck\fR command
+Process name may only contain letters, numbers and the underscore _ character. You can validate your Procfile format using the \fBcheck\fR command
 .
 .IP "" 4
 .
diff --git a/man/foreman.1.ronn b/man/foreman.1.ronn
index c1767c4..19bdb1b 100644
--- a/man/foreman.1.ronn
+++ b/man/foreman.1.ronn
@@ -113,7 +113,7 @@ to run it.
     web: bundle exec thin start
     job: bundle exec rake jobs:work
 
-You can validate your Procfile format using the `check` command
+Process name may only contain letters, numbers and the underscore _ character.You can validate your Procfile format using the `check` command
 
     $ foreman check