Ultrasonography has been used as an adjunct in managing pelvic infections when culdocentesis is contraindicated. Twenty-three of 42 women presenting with endometritis/salpingilis/peritonitis (ESP) had ultrasonographic masses. The erythrocyte sedimentation rate (ESR), white blood cell count (WI3C), and the highest temperature in the first 24 hours failed to distinguish those with sonographic masses from 19 patients without pelvic masses. The clinical parameter that tended to distinguish patients with masses versus no masses occurred in individuals who had an IUD at the time of admission. If a patient had an ESR>65 mm/hr and an IUD, sonography demonstrated a mass in 71.4% of the cases. The clinical response to multidrug therapy (bactericidal- bacteriostatic, bactericidal-bactericidal, and tripledrug therapy) were comparable in the patient populations with or without a sonographic mass. Sonography is of little use in the acute phase of ESP. It is best reserved for those patients who do not respond to adequate antibiotic therapy and for the serial evaluation of a large tubo-ovarian complex when conservative management is indicated.