Twenty-six cases of unruptured tubal pregnancy were treated by laparoscope-guided injection of prostaglandin (PG) F2 alpha into the affected tube and the ovary containing the corpus luteum. Preoperative serum human chorionic gonadotropin (hCG) levels were 22 to 2,050 IU/L (mean 328 IU/L). The procedure was successful in 24 patients (92%), as indicated by reduction of hCG values to less than 20 IU/L. The remaining 2 cases showed an initial fall in hCG after injection and thereafter a plateau phase indicating the persistence of trophoblast. In both cases, a second surgical intervention was necessary. The total subsequent conception rate among 19 women desiring pregnancy was 90% (17/19). The intrauterine conception rate was 58% (11/19), and the repeat rate of ectopic pregnancy was 32% (6/19). Two-thirds (12/19) of the subsequent pregnancies occurred within 6 months "at risk" for conception. It is concluded that local injection of PGF2 alpha represents an attractive method for termination of selected cases of tubal pregnancy, preferentially in subjects with low trophoblastic activity.