Objective: Determine the frequency of hypothyroidism in recurrent pregnancy loss. Study Design: This is cross sectional. Place and Duration of Study: This study was conducted at Obstetrics and Gynaecology department of Dow Medical University & Hospital, Ojha Campus, Karachi, from 7th July 2018 to 6th July 2019. Methodology: This study was conducted on 83 patients. Detailed history was taken from all the patients with special regard to demographics like age, parity and recurrent pregnancy loss. A 3 ml venous blood was drawn by the staff on duty and sent to institutional laboratory for TSH and free T4 level. TSH values more than 4.5 μIU/L and normal free T4 level (0.7 to 1, 8 ng/ml) were considered as hypothyroidism. All pregnant female was between age 20-35 years with > 6 months gestational age and history of parity 3 and gravida 4 were included in the study. Exclusion criteria were known case of hypothyroidism or history of taking medication for hypothyroidism, history of Hypertension and DM. Results: This study was conducted on 83 patients. There was wide variation of age ranging from a minimum of 20 years to 35 years. The mean age was 28.4+ 4.49 years. Mostly patients were parity 3 and gravid 4 in 55(66.26%) cases followed by parity 4 and gravid 4 in 28(33.73%) cases. Gestational age was measured on ultrasound ranging from 8 weeks to 22 weeks. The mean gestational age was 14.20+4.71 years. Patient's thyroid profile mean Thyroid-stimulating hormone (TSH) level was 2.39+1.66 mU/L, mean free T4 was 17.23+6.41 nmol/L and mean free T3 was 4.87+1.18 μmol/L. Observed hypothyroidism was in 11(13.3%) cases while rest of 72(86.7%) cases within normal range. Conclusion: We concluded that hypothyroidism is problem in recurrent pregnancy loss. 11(13.3%) cases Frequency of hypothyroidism in women with pregnancy, the possible role of thyroid functional disorders in etiology of at least some part of recurrent pregnancy loss, had emphasized the importance of thyroid functions tests screening as routine in all pregnancies. Keywords: Thyroid disease, Pregnancy outcome, Hypothyroidism.