The extremely small ultrasound transducers of the intraluminal ultrasound instruments, introduced via catheters, enable diagnosis to be made inside hollow organs. In order to test the possible uses and indications for this new method in gynaecology, we conducted preliminary examinations in the diagnosis of the uterus and tubes. We employed an intraluminal instrument supplied by Dornier. The intraluminal transducers of this instrument have a diameter of 3.5 and 5 F. Following in-vitro examinations, hysteroscopy and laparoscopy/laparotomy were performed in 15 patients during which the transducer was pushed up via the cervix uteri to the tubes with full vision. This was successful in all 15 patients; in 9 cases the transducer could be pushed as far as the distal end. The tubal walls were examined in detail by this method and for the first time it became possible to achieve functional diagnosis of the motility of the tubes. Strictures can be visualised. The endometrium of the uterus, however, cannot as yet be diagnosed exactly by the present-day state of examination technique. If image quality can be further improved, this method will be the first to enable a functional diagnosis of the tubes and the uterus.