Postoperative acute pulmonary embolism (APE) can be a life-threatening emergency and is associated with very high mortality. Approximately two-thirds of patients, who died of pulmonary embolism, die within the first hour after the presentation. We report a case of APE following an emergency lower segment cesarean section (LSCS) because of severe fetal distress. This 37-year-old female with no previous medical or surgical history underwent LSCS under general anesthesia. The surgery was uneventful and she was extubated uneventfully at the end of surgery. Six hours after surgery, there was a sudden drop in oxygen saturation on pulse oximetry, tachypnea which raised the suspicion of APE. An urgent chest radiograph computed tomographic pulmonary angiography (CTPA) and transthoracic echocardiogram along a sample for D-dimer were ordered immediately. CTPA was consistent with APE involving the main pulmonary artery. Given immediate postoperative status, therapeutic anticoagulation was done using low-molecular-weight heparin. The patient was discharged 10 days later. APE is a potentially high-risk event that can be challenging in the postoperative period. A high index of suspicion and therapeutic anticoagulation with meticulous monitoring is required in such cases to reduce morbidity.