An insertion set (10) is provided for transcutaneous placement of a sensor (12) such as a glucose sensor at a selected site within the body of a patient. The insertion set (10) comprises an insertion needle (14) extending through a mounting base (34) adapted for mounting onto a patient's skin. A flexible thin film sensor (12) includes a proximal segment (20) carried by the mounting base (34) and adapted for electrical connection to a suitable monitor and a distal segment (16) protruding from the mounting base (34) with sensor electrodes (18) thereon for transcutaneous placement. The distal segment (16) of the sensor (12) and a distal segment (66) of the insertion needle (14) are positioned within a flexible cannula (15) which extends from the mounting base (34), whereby placement of the mounting base (34) onto the patient's skin causes insertion needle (14) to pierce the skin for transcutaneous placement of the cannula (15) with the sensor (12) therein.
