diff --git a/lib/amorail/entity.rb b/lib/amorail/entity.rb
index 8e1f702..68c3e06 100644
--- a/lib/amorail/entity.rb
+++ b/lib/amorail/entity.rb
@@ -33,7 +33,7 @@ def amo_field(*vars, **hargs)
       end
 
       def amo_property(name, options = {})
-        properties[name] = options
+        properties[name.downcase] = options
         attr_accessor(options.fetch(:method_name, name))
       end