Arsenic poisoning is a major public health concern in Bangladesh. This study uses primary data to examine health impacts and costs associated with arsenic contamination of groundwater. The study estimates that some 7 to 12 million person-days per year are lost as a result of arsenic exposure. In addition, individuals who are sick spend between 207 (US$ 3.5) million to 369 (US$ 6.25) million taka per year for medical help. The total cost of illness as a result of exposure to arsenic is Tk 557 (US$ 9) to Tk 994 (US$ 17) million per annum or on average nearly 0.6 percent of the annual income of affected individuals. If it is possible to provide arsenic-free (within safe limit) alternative technologies to reverse the impact of arsenic, the social gains to Bangladesh are considerable. The study also finds that the threat of Melanosis--the black spot disease-andKeratosis-roughness in palms and soles- is high when there is cumulative exposure and that this threat is not the same for all wealth classes. Richer households take mitigation measures to reduce the threat on their health. Richer households also seem to be more successful in avoiding the incidence of conjunctivitis due to Arsenicosis. Women on the other hand are more likely to be affected by inflammation of the respiratory tracts--a sign of long-term exposure without recourse to medical help.