Background <p>Twin ectopic pregnancy is an exceptionally rare and potentially life-threatening condition, particularly when both embryos implant within a single fallopian tube. Diagnosis relies primarily on transvaginal ultrasonography and serum beta-human chorionic gonadotropin measurement, with early detection being critical to preventing tubal rupture. In some cases, diagnosis may be complicated by atypically elevated beta-human chorionic gonadotropin levels that can mimic early intrauterine gestation. We report a rare case of unilateral tubal twin ectopic pregnancy that was successfully diagnosed and surgically managed.</p> Case presentation <p>We report a case of a 34-year-old woman of Russian Slavic ethnicity who presented with mild vaginal bleeding and markedly elevated serum beta-human chorionic gonadotropin levels. Transvaginal ultrasonography revealed two adjacent gestational sacs with fetal poles in the left adnexa and no evidence of an intrauterine pregnancy. Laparoscopy confirmed an unruptured ampullary twin ectopic pregnancy, and a left salpingectomy was performed. Histopathological examination demonstrated avascular chorionic villi, extravillous cytotrophoblasts, and extensive intratubal hemorrhage, confirming the diagnosis. The postoperative course was uneventful.</p> Conclusion <p>This case highlights the diagnostic challenges associated with twin ectopic pregnancy and emphasizes that elevated beta-human chorionic gonadotropin levels do not exclude an ectopic gestation. Early imaging and timely surgical intervention are essential to preventing tubal rupture, reducing maternal morbidity, and preserving reproductive health.</p>