A new technique, using an intraluminally placed dacron catheter carrying an ultra miniature pressure sensor (MIKRO-TIP, PR-249, Millar Instr., USA) was designed for recording spontaneous intraluminal pressure variations which reflected contractions in the oviductal wall. The catheter was passed subcutaneously from the lumbar back of the animal to the flank where an incision had been made. The distal end of the catheter was passed from a small incision in the uterus tip 2 cm into the isthmus of the oviduct. The catheter's position was secured and control recordings made by connecting the catheter's electrical connector to a polygraph. During the subsequent 24-48 hours successful recordings were made at frequent intervals. Peripheral blood was collected in connection with each recording to monitor ovarian functions.