Background: Hysteroscopy is a well-established diagnostic and surgical technique that is widely used to diagnose and treat a wide range of common gynaecological abnormalities involving the uterine cavity. It is also a critical diagnostic step in the treatment of infertility. The aim of this work was to evaluate the role of diagnostic hysteroscopy (DHL) in the comprehensive work-up of unexplained infertility, which would help in planning appropriate management. Methods: This prospective study was conducted at department of Obstetrics and Gynecology, at Zagazig University Hospital during the period study year July 2020 to December 2020. Included 80 patients infertile women aged between 18 to 42 years with either primary or secondery infertility. All patients had normal Hysterosalpingography, with normal hormone profile and without male factor infertility and normal TVS. Results: In the current study normal hysteroscopy was found in 50 cases (62.5%) and abnormal hysteroscopy was found in 30 cases (37.5%), 20 (25%) were complaining of primary infertility while 10 (12.5%) were complaining of secondary infertility. the frequency of women with arcuate uterus, bicornuate uterus and very small uterine cavity are significantly increased in Primary infertility group (20%, 15% and 10% respectively) than secondary infertility group. And the frequency of women with intrauterine synechia and bilateral narrow corneal end are significantly higher in secondary infertility group (30 % of both) than Primary infertility group. Conclusions: Hysteroscopy remains the gold standard for the evaluation of the uterine cavity.