Interstitial pregnancy is a rare form of ectopic pregnancy, but it is associated with the highest risk of morbidity and mortality and needs early diagnosis. Interstitial, angular and cornual pregnancies are mistakenly and frequently confused and need a strict distinction. Interstitial pregnancy refers to an ectopic pregnancy that is implanted in the interstitial portion of the fallopian tube. Its correct diagnosis can be quite difficult; it relies heavily on quantitative beta-hCG assays and ultrasound and potentially on laparoscopic evaluation. The diagnosis by transvaginale ultrasonography is based on multiple criteria. Several effective treatment options for treatment of interstitial pregnancy have been described but the most appropriate technique remains controversial. Managing an interstitial pregnancy is dependent upon whether the ectopic pregnancy has ruptured, the stability of the patient, the gestational age at diagnosis and the patient's desire for future fertility. The greatest risk to patients after successful treatment remains recurrence of interstitial pregnancy and the uterine rupture during subsequent pregnancy this is why a transvaginale ultrasonography should be performed 5-6 weeks after the last menstrual period and a cesarean delivery should be planned at term or performed, if tocolysis fails in cases of preterm labor. To illustrate the particularities of this form of ectopic pregnancy we report two cases with a brief up date.