Objective: To determine the frequency of intrauterine abnormalities in women with unexplained infertility using saline infusion sonography. Material and methods: This was a retrospective cohort study conducted at Aziz medical centre, Karachi, Pakistan between January and December 2015. The study population comprised of women with unexplained infertility who underwent saline infusion sonography as a part of their diagnostic workup. The frequency of uterine abnormalities in these women was determined and the relationship between these pathologies and patient age and body mass index was assessed. Results: Of the 769 women included, 202 (26.3%) had uterine abnormalities. Endometrial polyp (118 cases, 15.3%) was the most common abnormality, followed by submucous fibroids (54, 7%), intrauterine adhesions (20, 2.6%), and septae (10, 5%). Intrauterine pathologies were more common in women with primary infertility (71.8% versus 28.2%, p = 0.002). Uterine abnormalities were most common in the age group 30–34 years (n = 80, 39.6%) and in overweight patients (n = 95, 47%). The distribution of abnormalities differed significantly in various age groups (p = 0.009) and among women with different BMI (p = 0.029). Conclusions: A significant number of women with unexplained infertility present with unsuspected uterine abnormalities; therefore an assessment of the uterine cavity should be performed in all cases.