diff --git a/lib/fog/aws/models/compute/server.rb b/lib/fog/aws/models/compute/server.rb
index 640064f8d..59124422c 100644
--- a/lib/fog/aws/models/compute/server.rb
+++ b/lib/fog/aws/models/compute/server.rb
@@ -178,11 +178,9 @@ module Fog
               options['NetworkInterface.0.AssociatePublicIpAddress'] = associate_public_ip
               options['NetworkInterface.0.SubnetId'] = options['SubnetId']
               options.delete('SubnetId')
-              grp_num = 0
               if options['SecurityGroupId'].kind_of?(Array)
                 options['SecurityGroupId'].each {|id|
-                  options["NetworkInterface.0.SecurityGroupId.#{grp_num}"] = id
-                  grp_num += 1
+                  options["NetworkInterface.0.SecurityGroupId.#{options['SecurityGroupId'].index(id)}"] = id
                 }
               else
                 options["NetworkInterface.0.SecurityGroupId.0"] = options['SecurityGroupId']