BACKGROUND: There has been an increasing number of elderly patients with intraductal papillary mucinous neoplasm (IPMN), who are surgically intolerant and require less invasive treatment options, which are limited. In the present study, we report a case of IPMN presenting with acute recurrent pancreatitis (ARP), in which radiation therapy effectively prevented further attacks of ARP and reduced tumor volume. CASE SUMMARY: An 83-year-old man was referred to our hospital with an asymptomatic incidental pancreatic cyst. Endoscopic ultrasound imaging and magnetic resonance cholangiopancreatography revealed a multiloculated tumor in the head of the pancreas, with dilated pancreatic ducts and mural nodules. The patient was diagnosed with mixed-type IPMN, and five years later, he developed ARP. Several endoscopic pancreatic ductal balloon dilatations failed to prevent further ARP attacks. Surgery was considered clinically inappropriate because of his old age and comorbidities. He was referred to our department for radiation therapy targeted at those lesions causing intraductal hypertension and radiation was administered at a dose of 50 Gy. An magnetic resonance imaging scan taken ten weeks after treatment revealed a decrease in tumor size and improvement of pancreatic duct dilatation. Fourteen months later, he remains symptom-free from ARP. CONCLUSION: This case highlights the important role of radiation therapy in mitigating the signs and symptoms of ARP in patients with inoperable IPMN.