diff --git a/lib/crono/period.rb b/lib/crono/period.rb
index 65d27e5..40210c1 100644
--- a/lib/crono/period.rb
+++ b/lib/crono/period.rb
@@ -20,6 +20,7 @@ module Crono
     def description
       desc = "every #{@period.inspect}"
       desc += format(' at %.2i:%.2i', @at_hour, @at_min) if @at_hour && @at_min
+      desc += " on #{DAYS[@on].capitalize}" if @on
       desc
     end
 
diff --git a/spec/period_spec.rb b/spec/period_spec.rb
index b8a8543..2a34c8a 100644
--- a/spec/period_spec.rb
+++ b/spec/period_spec.rb
@@ -9,8 +9,8 @@ describe Crono::Period do
 
   describe '#description' do
     it 'should return period description' do
-      @period = Crono::Period.new(2.day, at: '15:20')
-      expect(@period.description).to be_eql('every 2 days at 15:20')
+      @period = Crono::Period.new(1.week, on: :monday, at: '15:20')
+      expect(@period.description).to be_eql('every 7 days at 15:20 on Monday')
     end
   end