A delivery device includes a durable housing portion and a separable disposable portion that selectively engage and disengage from each other. The disposable housing portion contains a reservoir and secures to the patient and may be disposed of after it has been in use for a prescribed period. A disposable pump assembly selectively connects to the reservoir. The disposable pump assembly includes a pump rotor, a septum and a needle for conveying infusion media from the reservoir to the patient.