diff --git a/app/models/invitation.rb b/app/models/invitation.rb
index 97cbc6c..dc3b2af 100644
--- a/app/models/invitation.rb
+++ b/app/models/invitation.rb
@@ -65,18 +65,16 @@ class Invitation < Task
 
       task_args = if user.nil?
         {:person => person, :friend_name => friend_name, :friend_email => friend_email, :message => message}
-      elsif !user.person.is_a_friend?(person)
+      else
         {:person => person, :target => user.person}
       end
 
-      if !task_args.nil?
-        if profile.person?
-          InviteFriend.create(task_args)
-        elsif profile.community?
-          InviteMember.create(task_args.merge(:community_id => profile.id))
-        else
-          raise NotImplementedError, 'Don\'t know how to invite people to a %s' % profile.class.to_s
-        end
+      if profile.person?
+        InviteFriend.create(task_args) if user.nil? || !user.person.is_a_friend?(person)
+      elsif profile.community?
+        InviteMember.create(task_args.merge(:community_id => profile.id)) if user.nil? || !user.person.is_member_of?(profile)
+      else
+        raise NotImplementedError, 'Don\'t know how to invite people to a %s' % profile.class.to_s
       end
     end
   end
diff --git a/test/unit/invitation_test.rb b/test/unit/invitation_test.rb
index 9728c50..054fc2d 100644
--- a/test/unit/invitation_test.rb
+++ b/test/unit/invitation_test.rb
@@ -60,6 +60,19 @@ class InvitationTest < ActiveSupport::TestCase
     end
   end
 
+  should 'not create task if the invited member is already a member of the community' do
+    person = fast_create(Person)
+    person.user = User.new(:email => 'current_user@email.invalid')
+    community = fast_create(Community)
+    user_to_invite = fast_create(User, :email => 'person_to_invite@email.invalid')
+    person_to_invite = fast_create(Person, :user_id => user_to_invite.id)
+    community.add_member(person_to_invite)
+
+    assert_no_difference 'InviteMember.count' do
+      Invitation.invite(person, ['person_to_invite@email.invalid'], 'hello friend <url>', community)
+    end
+  end
+
   should 'not crash if the invited friend is already your friend in the environment' do
     person = create_user('person').person
     invited_friend = create_user('invited_friend').person
--
libgit2 0.21.2