Aim: To find out incidence of post-dated pregnancies, associated maternal complications and perinatal morbidity and mortality. Material and Methods: This was a retrospective observational study conducted in the Department of obstetrics and gynaecology, Anugrah Narayan Magadh Medical College, Gaya, Bihar, India for 15 months. Total 160 patients in the antenatal ward and labour room were selected for the study and they were divided into two groups, Control group with Gestational age 37-40 weeks and Study group with Gestational age >40 weeks. The maternal outcome was noted in terms of need for cesarean section, postpartum haemorrhage and sepsis. Foetal outcome was noted in terms of intrapartam asphyxia, intrauterine foetal death, admission to neonatal intensive care unit etc. Results: The maximum number of patients belonged to the age group of 25-30 years both in cases (56.25%) and control group (53.75%) and the maximum number of patients in the study group (75%) belonged to the gestational age of 40-41 weeks while all the controls belonged to 37-40 weeks gestational age. in this study 63.75% of the patients in study group were primigravida and in the control group 53.75% were primigravida. The study group the percentage of LSCS was 28.75% which was higher than in the control group where it was 12.5%. Incidence of instrumental delivery was also higher in the study group as compared to control group (10% as compared to 3.75%). Among the indictions for LSCS, the most common indication among the study group was acute foetal distress which includes meconium stained liquor (11.25%) followed by cephalopelvic disproportion (6.25%). In the control group, most common indication was non progress of labour (5%) followed by acute foetal distress (3.33%) and non reactive CTG (3.33%). The maternal complications like LSCS, PPH and sepsis all were higher in the study group as compared to the control group. Among the foetal outcomes, 13.75% of infants in the study group had asphyxia as compared to only 6.25% in the control group. 15% infants of the study group had to be admitted to the NICU as compared to 11.25% in the control group. 1.25% was the percentage of intrauterine deaths in the study group as compared to none in the control group. Conclusion: Considering this, policy of early intervention should be undertaken in post-dated pregnancy to avoid maternal and perinatal complications.