Purpose of investigation: To evaluate pregnancy rate after diagnostic and operative hysteroscopy in nulliparous patients with infertility of unknown cause. Materials and Methods: The authors conducted this study on 92 nulliparous patients with unexplained infertility that underwent diagnostic hysteroscopy which showed an uterine lesion (submucous fibroids, uterine septa, polyps, synechias) and underwent operative hysteroscopy to remove the lesion between 2007 and 2011. Patients’ data were retrospectively extrapolated from patient’s charts, then the patients were called to ask if they had pregnancies after hysteroscopic surgery. Results: The present study showed a significant increase in pregnancy rate after hysteroscopic surgery (85% during the two years after the surgery). The most common endocavitary lesions were endometrial polyps (21%), uterine septa (25%), and submucous myomas (18%). Conclusions: According to the present data, hysteroscopic evaluation of nulliparous women with unexplained infertility could be useful to detect lesions not diagnosed with other tests, and the treatment of these endocavitary lesions plays an important role in the diagnostic and therapeutic iter. The results show a pregnancy rate of 85% in the patients treated for endocavitary lesions, but 15% of the patients, despite a normal uterine cavity, continue to have unexplained infertility and are classified as idiopathic infertility.