An analysis was made of the records of 328 cases of ectopic pregnancy seen during a 5-year period (1975-79) with respect to history, clinical features, diagnostic tools and surgical procedures. Special attention was paid to the methods used to obtain an early diagnosis. The best methods in this respect were found to be laparoscopy and determination of serum chorionic gonadotropin. Ultrasonography was performed in too few cases to permit an evaluation of the sensitivity of the method. However, 25% of the cases presented with a gestational time of 6 weeks or less, a period during which ultrasound is known to be uncertain in the diagnosis of pregnancy, and only 33% of the cases with a time of 9 weeks or more when ultrasound is considered to be highly reliable for this diagnosis.