Chlordecone, an insecticide with estrogen-like hormonal properties, was used on banana plantations in the French West Indies from 1973 to 1993, leading to soil contamination and exposure among the population. The Karuprostate study analyzed the relationship between exposure to chlordecone and the risk of developing prostate cancer. Here we describe the context that led to the conduct of this study and its main conclusions. (R.A.)