Selective venography has become a routine diagnostic procedure. Adrenal venography for the definition of masses and for hormone analysis has proved valuable. Recently gonadal venography has been used in the evaluation of varicocele and infertility (1, 3, 4) and Delorme et al. recently catheterized the left gonadal vein (5). It was our intention in this investigation to establish the technic for venography of both the left and right gonadal systems and to determine its clinical usefulness. Numerous anatomic variations were encountered which have not been previously described and which affect the approach to the procedure. The simultaneous selective sampling of gonadal and adrenal hormones is being used in the endocrinologic evaluation of the gonadal syndromes and will be the subject of a further communication. Material Twenty-eight patients have been studied. Twelve were males: 3 with cryptorchidism, 1 with undescended testicle, 1 with Klinefelter's syndrome, 2 with varicocele, and the remainder with abdominal malignancies. Of the 16 females, 6 had Stein-Leventhal syndrome, 2 had adrenal tumors, 1 an ovarian mass, and the remainder had trophoblastic disease. We have found this procedure to be free of significant morbidity. No discomfort is experienced during contrast injection. Four of our patients have undergone pelvic surgery within a week of the procedure. The ovarian veins were examined, and there was no evidence of phlebitis or traumatic residuals. Methods All studies consist of bilateral adrenal and gonadal vein catheterization. The adrenal vein technic has been described by others. The gonadal procedure can usually be accomplished from the right femoral vein. There are occasions, however, when the angle of incidence of the right gonadal vein is so acute, relative to the inferior vena cava, that the percutaneous jugular approach may be necessary. The clinical indications for catheterization of the vein in question dictate the need for a second approach. The jugular approach has proved simple and free of complications in our hands and was the primary approach in 6 patients. The patient experiences more local discomfort, however, and 75 per cent of the time a complete study can be accomplished from the femoral vein. We have found the Muller guided catheter system (USCI) to be useful in this procedure and are now using it exclusively. Before this system was available to us, preformed catheters were used with some success. The major disadvantage of preformed catheters is the inability to negotiate the frequently encountered valves or anastomotic vessels. With the Muller system, the catheter can usually be passed through or past such obstacles. A disadvantage of this system in its present form is that the wire must be removed for sampling. This is particularly disappointing when the right adrenal vein is approached from below. In this situation, the maintenance of the curve is necessary to stay in the vein.