A 49-year-old female patient on continuous ambulatory peritoneal dialysis presented with fever, abdominal pain and loss of appetite. While peritoneal fluid bacterial cultures remained negative, she had no relief after 3 weeks of broad-spectrum antibiotics for possible bacterial peritonitis. In a peritoneal fluid sample, Mycobacterium tuberculosis DNA was detected by nucleic acid amplification using real-time PCR testing. The initiation of antituberculous therapy (isoniazid, rifampicin, ethambutol and pyrazinamide) was followed by resolution of fever and abdominal pain within one week. Nucleic acid amplification tests can play an important role in the species-specific diagnosis of tuberculous peritonitis.