The tubal capacity to transport radioactively labeled human albumin microspheres deposited in the vaginal fornix and cervical canal and to concentrate them on the ovarian surface was evaluated in a group of 34 patient-volunteers. One millicurie of technetium-99 was used to label human albumin microspheres of 20 mu in diameter, suspended in 1 ml of saline. The distribution of the radioactive material was imaged on a gamma camera at different intervals between 15 and 240 minutes. The radiation dose to the ovaries was estimated to be similar to that of a hysterosalpingogram. The results of the radionuclide evaluation were compared with the surgical findings at the time of laparoscopy or laparotomy performed for diagnostic or therapeutic reasons. The overall correlation was 87.1%. It would appear that as opposed to the traditional hysterosalpingogram, a radionuclide test may give a better understanding of the functional capacity of the tube and may also prove a useful method in the evaluation of the results of tubal microsurgical procedures.