diff --git a/src/package.coffee b/src/package.coffee
index 65442bf6f..dcb64056d 100644
--- a/src/package.coffee
+++ b/src/package.coffee
@@ -146,6 +146,9 @@ class Package
       if @mainModule.config? and typeof @mainModule.config is 'object'
         atom.config.setSchema @name, {type: 'object', properties: @mainModule.config}
       else if @mainModule.configDefaults? and typeof @mainModule.configDefaults is 'object'
+        deprecate """Use a config schema instead. See the configuration section
+        of https://atom.io/docs/latest/creating-a-package and
+        https://atom.io/docs/api/latest/Config for more details"""
         atom.config.setDefaults(@name, @mainModule.configDefaults)
       @mainModule.activateConfig?()
     @configActivated = true