Pantoprazole is a proton-pump inhibitor (PPI) that is commonly prescribed for the treatment of gastroesophageal reflux-related disorders. There are many documented side effects of PPIs. Here we report a case of acute interstitial nephritis, which developed after 6 weeks of treatment with pantoprazole. A 23-year-old man presented with acute renal failure requiring renal replacement therapy. Acute interstitial nephritis was diagnosed by renal biopsy and was successfully treated with corticosteroids and withdrawal of pantoprazole. Drug-induced acute interstitial nephritis can occur with PPIs such as pantoprazole and vigilance needs to be maintained.