Whipple's disease (WD) is a rare, chronic, systemic infection caused by the bacterium Tropheryma whipplei. New molecular techniques and epidemiological data over the latest decade have contributed to better understanding of this infection. The classical form of WD is characterized by arthritis followed years after by diarrhoea, weight loss and malabsorption but other clinical forms without intestinal involvement have been described. Prompt recognition and treatment of the infection is important, as the disease can be fatal if untreated. New studies are required to establish the optimal therapy regimen.