AbstractBetween March 2005 and May 2006, Réunion Island was hit by an epidemic of chikungunya which affected 260,000 people (38% of the island’s population). Chikungunya is a viral disease transmitted through mosquito bites for which there is no effective treatment. A socio-epidemiological survey was conducted in May 2006 on a representative sample of the population (N=1,035) which aimed to identify the factors related to high probability of contamination : on the one hand, objective socio-economic, demographic and environmental factors and, on the other hand, subjective factors such as perceptions of risk, the disease and the available methods of protection, knowledge and beliefs about the origin of the disease and how it is transmitted, attitudes and protection methods employed. This analysis shows that contamination is significantly associated with : 1) a socioeconomic status characterizing disadvantaged people living in individual houses with gardens ; 2) the existence of « alternative » (not scientifically proven) beliefs which, along with a fatalistic attitude, create a sense of being powerless to prevent contamination. As far as behaviours are concerned, only the frequent use of repellent sprays and creams was found to be positively associated with a reduced probability of contamination. In sum, factors such as socioeconomic conditions, place of residence, belief systems and behaviours were all closely interdependent, forming socio-cultural models that were more or less favourable to contamination.