The purposes of this study were to evaluate the accuracy of pelvic sonography in identification of adenomyosis and to characterize the most commonly seen sonographic features. We identified all patients over a 10 year period in whom a prospective diagnosis of adenomyosis was suspected on the basis of sonographic findings and who had undergone hysterectomy at a single hospital. Patients were referred for sonography based on standard indications. Sonographic features used in the diagnosis of adenomyosis consisted of two or more of the following: a mottled inhomogeneous myometrial texture, globular appearing uterus, small cystic spaces within the myometrium, and a "shaggy" indistinct endometrial stripe. Correlation was made with the pathology report on the hysterectomy specimen. Fifty-one women met the study criteria. Forty-three of 51 (84.3%) patients sonographically suspected of having adenomyosis were confirmed as having adenomyosis by pathologic examination. All patients with adenomyosis had a mottled heterogeneous appearing uterus, 95% had a globular uterus, 82% had small myometrial lucent areas, and 82% had an indistinct endometrial stripe. Eight patients (15.6%) who had been suspected of having adenomyosis by pelvic sonography did not have adenomyosis reported in the pathology specimen. Six of these eight (75%) patients had multiple small fibroids, one had stage IV endometriosis, and one had a normal uterine specimen with no evidence of pathology. Pelvic sonography provides an accurate diagnosis of adenomyosis in the majority of cases.