OBJECTIVE: To evaluate the accuracy of gynecologic surgeons at estimating uterine dimensions and weight. METHODS: Six model uteri of various sizes were created to simulate the size and consistency of a uterus and displayed at 3 stations. The visual station (VS) comprised 2 specimens placed on an unmarked table. The laparoscopic station (LS) consisted of 2 model uteri, each placed in a separate simulated abdomen with a 0 degree laparoscope and 2 operative trocars with standard instruments. The blind weight station (BWS) consisted of blind palpation of 2 separately weighted models (heavy model [HM] and light model [LM]). Participants visually estimated the dimensions of each VS and LS models and blindly palpated the BWS models to estimate weight. RESULTS: Participants included 15 residents, 27 attendings, and 6 medical students. There was no difference in estimation accuracy regarding gender and age. For the VS and LS groups, participants underestimated all dimensions (VS variance = -15.0%; P < 0.001 and LS variance = -31.9%; P < 0.0001). Laparoscopic estimation was less accurate than direct vision (P < 0.0001). Attendings and residents equally underestimated the 3 dimensions visually (P = 0.46), but attendings were more accurate at estimating laparoscopic dimensions (-25.8% vs -41.1%; P = 0.0001). All groups overestimated model weights (HM variance, 92.5%; P < 0.001 and LM variance, 132.0%; P < 0.0001), with attendings more accurate than residents (39.7% vs 167.6%; P = 0.015 for HM and 52.0% vs 238.5%; P = 0.035 for LM). CONCLUSIONS: Gynecologic surgeons at all levels of training are inaccurate at estimating dimensions and weights. With surgical decisions often predicated on estimates, education is needed to improve estimation methods.