Engine is overheating even though there is anti-freeze in it.

cooling fans working? any work done on the coolant system recently,anything? is the coolant/antifreeze level full?

Start your engine when it's still cold. Open the radiator cap. Check the fluid for circulation when the engine was hot (fan on) If not, thermostat was stuck (it didn't open the valve for water go through) Worse than that, water pump failed.