diff --git a/lib/pardot/objects/list_memberships.rb b/lib/pardot/objects/list_memberships.rb
index db0354c..8c62c0d 100644
--- a/lib/pardot/objects/list_memberships.rb
+++ b/lib/pardot/objects/list_memberships.rb
@@ -22,6 +22,10 @@ def read_by_id id, params = {}
           get "/do/read/id/#{id}", params
         end
 
+        def create list_id, prospect_id, params = {}
+          post "/do/create/list_id/#{list_id}/prospect_id/#{prospect_id}", params
+        end
+
         protected
 
         def get path, params = {}, result = "listMembership"
@@ -29,6 +33,11 @@ def get path, params = {}, result = "listMembership"
           result ? response[result] : response
         end
 
+        def post path, params = {}, result = "listMembership"
+          response = @client.post "listMembership", path, params
+          result ? response[result] : response
+        end
+
       end
 
     end
diff --git a/ruby-pardot.gemspec b/ruby-pardot.gemspec
index 4e46b42..924f6f3 100644
--- a/ruby-pardot.gemspec
+++ b/ruby-pardot.gemspec
@@ -15,7 +15,7 @@ Gem::Specification.new do |s|
   s.rubyforge_project         = "ruby-pardot"
 
   s.add_dependency "crack", "0.4.3"
-  s.add_dependency "httparty", "0.13.1"
+  s.add_dependency "httparty"
 
   s.add_development_dependency "bundler", ">= 1.10"
   s.add_development_dependency "rspec"