Melioidosis is an emerging zoonosis, due to Burkholderia pseudomallei, which is a highly invasive, resistant, and resilient soil bacteria, transmitted by cutaneous or airborne route, and is a potential weapon for bioterrorism. Although the agent has been identified all over the world, the human disease is endemic only in SE Asia and Northern Australia, and gained recent interest after the December 2004 tsunami. Human infection can be a very severe systemic disease (mortality 20 to 80%), with protean expression, but the lung is the most affected organ (50%). Pathophysiology remains unclear. Diabetes mellitus is a major risk factor, and is present in half the Asian patients with melioidosis. Recommended antibiotic regimens are expensive, and in severe disease should be prolonged to 20 weeks to reduce the risk of relapse. Prospects for prevention are limited, and no vaccine is available yet.