We describe a middle-aged woman with Whipple's disease. She suffered from a seronegative rheumatoid-like polyarthritis for more than 20 years before the diagnosis of Whipple's disease was made. This case shows that arthritis may be a feature of occult Whipple's disease. Without gastrointestinal symptoms, diagnosis is very difficult. Diagnosis is important because treatment can rapidly improve this life-threatening disease.