We prospectively evaluated 29 patients with early postabortion or postpartum bleeding, suspected of having possible retained trophoblastic tissue by transvaginal sonography and transvaginal sonohysterography. All patients received methyl-ergometrine maleate (Sandoz) and amoxicillin and clavulinic acid (Pharmascope) orally for 5 days and were then reevaluated. Ten patients (34.5%) had a normal uterine cavity on both transvaginal sonography and sonohysterography. Nineteen patients (65.5%) were suspected of having residual trophoblastic tissue by transvaginal sonography. Of these, five (26%) showed normal uterine cavity by sonohysterography. One patient (8.3%) reported heavy bleeding with clots after the conservative treatment. Repeated examination revealed normal uterine cavity. The remaining patients underwent curettage, and histopathologic examination revealed trophoblastic tissue. Transvaginal sonohysterography is more accurate than transvaginal sonography for diagnosing residual trophoblastic tissue in patients with postpartum and postabortion bleeding. Its use may eliminate unnecessary curettage procedures.