We evaluated marking and radiotelemetry techniques of Oregon spotted frogs (Rana pretiosa) from October, 1996, through December, 2000, at Dempsey Creek, Thurston County, Washington. Knee tags (plastic, numerically-coded fingerling tags tied at the knee) and PIT tags (passive integrated transponders) were used to uniquely identify individuals. Transmitters weighing 1 to 1.8 g were attached to frogs using 5-mm wide nylon ribbon belts threaded through a tube at the anterior end of the transmitter. Four knee-tagged frogs exhibited skin and muscle lacerations and the technique was abandoned early in the study. PIT tags were expensive but proved to be convenient and reliable. The nylon ribbon transmitter attachment, applied 94 times, allowed us to monitor individual frogs for an average of 57 d but sometimes caused skin abrasions and had a 34% loss rate. We suggest ways to improve transmitter retention and prevent harm to frogs.