OBJECTIVE: To compare the severity of pelvic organ prolapse between examinations performed in dorsal lithotomy position and examinations performed upright in a birthing chair using the Pelvic Organ Prolapse Quantification System (POPQ). METHODS: One hundred eighty-nine consecutive women were evaluated between April 1997 and September 1998. All women were examined in the dorsal lithotomy position and in a birthing chair at a 45 degrees angle. Degree of pelvic organ prolapse was assessed using the POPQ. RESULTS: When examined upright, 133 patients (70%) had the same stage of prolapse, whereas 49 (26%) had a higher stage and seven (4%) had a lower stage. Of patients who were stage 0 or I when examined in lithotomy position, 23 (36%) were stage II or greater when examined upright. Similarly, of patients who were stage II in lithotomy, 17 (23%) were stage III or higher when examined upright. There was a statistically significant increase in the degree of prolapse at all the POPQ measurements (P <.05 for each point), except for measurement of total vaginal length. Forty-eight percent of patients had at least one measurement increase by 2 cm or more when examined upright. Logistic regression identified no patient characteristics that were independently associated with a significant increase in stage or POPQ values with change in examination position. CONCLUSION: The degree of pelvic organ prolapse assessed with the patient in the lithotomy position correlates well with assessment performed upright; however, overall there is a higher degree of prolapse with upright examination.