A system and method for detecting the presence of a medicament reservoir within the housing of an infusion pump. A medicament reservoir, affixed to a reservoir cap is removably inserted within the housing of an infusion pump. A magnet is affixed to or embedded in one or both of the reservoir or the reservoir cap. Alternately, the cap or the reservoir can be made of magnetic material. A sensing device embedded or otherwise affixed to the pump housing senses the presence or absence of the magnetic field created by the magnet. The presence of the magnetic field indicates that the reservoir is inserted properly within the housing and the absence of the magnetic field indicates that the reservoir has been at least partially withdrawn from the pump's housing.