A young woman presented with right upper quadrant abdominal pain exacerbated by movement and breathing. Extensive evaluation revealed no gallstones or any other specific cause. Urine polymerase chain reaction results for Chlamydia trachomatis were positive, so the clinical diagnosis of Fitz-Hugh-Curtis syndrome was confirmed. This type of localized peritonitis is thought to be a complication of an ascending genital infection leading to pelvic inflammatory disease. The diagnosis is established on clinical grounds after excluding alternative, more common conditions. Proper antibiotic treatment usually leads to recovery and prevents long-term complications.