A method for performing ranging is disclosed. The method for performing ranging in a wireless communication system which simultaneously supports a legacy system and a new system includes a method for additionally allocating a ranging channel to a zone other than a legacy zone and a method for re-using a legacy ranging channel within the legacy zone. When the legacy ranging channel is re-used, ranging codes may be shared by a legacy mobile station and a new system mobile station or may be separated on a ranging code domain. Limited radio resources can be effectively employed by re-using the legacy ranging channel.