Twelve cases of fallopian tube dilatation were diagnosed in 10 patients by using endovaginal sonography. The diagnosis was confirmed by surgery in seven patients and by hysterosalpingography in three. A tubular shape was present in every case. Other sonographic features included a well-defined echogenic wall, a folded configuration, and linear echoes protruding into the tube lumen. Dilated tubes were distinguished from bowel loops by a lack of peristaltic activity and from pelvic veins by a lack of moving low-level echoes on real-time sonography. We conclude that the findings of dilated fallopian tubes on endovaginal sonography are sufficiently characteristic to allow the diagnosis to be made with this technique.