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 (