Objective: To determine how board-certified reproductive endocrinologists vary in their approach to the clinical tests performed on the infertile couple. Design: A cross-sectional study to assess differences in the approach to evaluating the infertile couple. Setting: A population- based national survey. Participant(s): United States board-certified reproductive endocrinologists. Main Outcome Measure(s): The frequency of clinical tests and evaluation procedures by physician age, sex, size and setting of practice, institutional affiliation, and geographic location. Result(s): The overall response rate was 84%. Although the majority of practitioners routinely order a semen analysis (99.9%), an assessment of ovulation (98%), a hysterosalpingogram, (HSG; 96%), laparoscopy (89%), and a postcoital test (PCT, 79%), there was less agreement regarding hormonal testing (range, 22% [LH] to 66% [PRL]), use of pelvic ultrasounds (55%), hysteroscopy (53%), cervical cultures (range, 24% to 54%), and antisperm antibody testing (24%). Compared with male colleagues, female physicians order two to three times more cervical cultures and endometrial biopsies. Serum hormonal testing was two to three times more commonly ordered by younger (<40 years) compared with older physicians, and physicians in private practice twice as frequently ordered hormonal testing, cervical cultures, PCTs, and antisperm antibody studies compared with their academic-affiliated colleagues. Western U.S. physicians order hormonal tests and cervical cultures 50% less often than their midwest and eastern counterparts. Conclusion(s): Trained specialists rely heavily on five 'traditional' infertility tests: semen analysis, an assessment of ovulation, HSG, laparoscopy, and PCT. With regard to additional modes of testing, there is marked variability by physician sex, age, type of practice, and geographic location.