Abstract: A conformable medical sensor is provided that has particular applicability for positioning a pulse oximeter sensor relative to a patient appendage. In one embodiment, the sensor holder includes a patient engaging member that is plastically deformable to permit the sensor holder to be conformed to the patient appendage, and plastically deformable to provide a retention force relative to the patient appendage. For example, the engaging member may be bent into a first shape that disposes first and second portions of the sensor holder into an opposing relationship the for receiving a patient appendage therebetween. Once deformed, the engaging member may be elastically deformed to a second shape to provide a retention force so as to maintain the sensor holder and a sensor interconnected thereto in contact with the patient appendage.