Although acute postoperative pancreatitis is a relatively frequent complication after open biliary tract surgery and gastric surgery, acute pancreatitis after spine surgery is a rare complication. We report the first case of acute pancreatitis after posterior lumbar interbody fusion (PLIF) for spondylolisthesis that resolved with conservative treatment. A 53-year-old female patient received a PLIF from L3 to L5. The patient presented with persistent mild abdominal pain, nausea and vomiting several hours after the surgery. An abdominal CT revealed swelling of the head of the pancreas and free fluid around the pancreas. A gastroenterologist diagnosed acute pancreatitis and prescribed nafamostat mesilate, antibiotics and intravenous fluid therapy. The patient recovered gradually, and clinical symptoms disappeared. At 6 months after the operation, she had experienced no recurrence of abdominal symptoms, and solid spinal fusion was achieved. In previous studies, acute pancreatitis was reported as a complication after spine surgery for various spine diseases such as scoliosis and lumbar disorders. The procedures performed included anterior/posterior scoliosis surgery and anterior/posterior lumbar fusion surgery. We must consider the possibility of acute pancreatitis when unusual abdominal symptoms with elevated serum amylase levels occur after spine surgery. Prompt diagnosis and supportive therapy are essential to minimize morbidity and mortality.