Background: Pancreatic pseudocysts are a frequent complication of pancreatitis, usually managed by endoscopic ultrasound (EUS)-guided drainage. Rare anatomical variants such as situs inversus may complicate endoscopic management. Case history: A 45-year-old male with alcohol-related pancreatitis presented with early satiety and an epigastric bulge. Imaging revealed situs inversus with a large pseudocyst compressing the stomach. Endoscopic ultrasound-guided drainage was not feasible due to the unstable position in reversed anatomy. After unsuccessful attempts in left lateral and prone positions, cystogastrostomy was achieved in the supine position using a side-view endoscope, with placement of a double pigtail plastic stent. The patient improved, developed transient low-grade fever, was managed conservatively, and was discharged. At 4 weeks, the stent had passed spontaneously, and CT confirmed complete resolution. Conclusion: This is the first reported case of pseudocyst drainage in situs inversus performed using an ERCP scope in the supine position, demonstrating technical adaptability.