diff --git a/modpol/orgs/orgs.lua b/modpol/orgs/orgs.lua
index 507210b..e22cbc1 100644
--- a/modpol/orgs/orgs.lua
+++ b/modpol/orgs/orgs.lua
@@ -225,6 +225,12 @@ end
 -- ===========================================
 -- adds a user to an org
 function modpol.orgs:add_member(user)
+    for id, name in ipairs(self.members) do
+        if user == name then
+            modpol.ocutil.log('Error in' .. self.name .. ':add_member -> user already in org')
+            return false
+        end
+    end
     -- trys to fill in empty spots first
     local empty_index = self:get_member_index('')
     if empty_index then
diff --git a/modpol/tests/org_basic_test.lua b/modpol/tests/org_basic_test.lua
index 96e112d..f6762c2 100644
--- a/modpol/tests/org_basic_test.lua
+++ b/modpol/tests/org_basic_test.lua
@@ -7,4 +7,17 @@ print('\nCreating an org called "test_org"')
 test_org = modpol.instance:add_org('test_org')
 
 print('\nTrying to create an org with the same name')
-duplicate = modpol.instance:add_org('test_org')
\ No newline at end of file
+duplicate = modpol.instance:add_org('test_org')
+
+print('\nAdding user "luke" to test_org')
+test_org:add_member('luke')
+
+print('\nTrying to add duplicate user to test_org')
+test_org:add_member('luke')
+
+print('\nRemoving user "luke" from test_org')
+test_org:remove_member('luke')
+
+print('\nTrying to remove user "luke" from empty member list')
+test_org:remove_member('luke')
+