Aim: To find out the 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 Gynaecology and Obstetrics in Patna medical college and Hospital, Patna, Bihar, India, for 10 months from February 2019 to October 2019. Total 240 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 37-40weeks and Study group with Gestational age >40weeks. 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: Maximum number of patients belonged to the age group of 25-30 years both in cases (54.17%) and control group (55.83%). The maximum number of patients in the study group (77.5%) belonged to the gestational age of 40-41 weeks while all the controls belonged to 37-40 weeks gestational age. 62.5% of the patients in study group were primigravida and in the control group 54.17% were primigravida. The percentage of LSCS was 27.5% which was higher than in the control group where it was 13.33%. Incidence of instrumental delivery was also higher in the study group as compared to control group (10.83% as compared to 3.33%). Among the indications for LSCS, the most common indication among the study group was acute foetal distress which includes meconium stained liquor (11.17%) followed by cephalopelvic disproportion (5.83%). In the control group, most common indication was non progress of labour (5.83%) followed by acute foetal distress (3.33%) and non reactive CTG (3.33%). The maternal complications like PPH and sepsis as well as fetal complications all were higher in the study group as compared to the control group. Conclusion: Considering this, policy of early intervention should be undertaken in post-dated pregnancy to avoid maternal and perinatal complications.