Concerning malaria, the role of the Reference National Centre on the Imported Diseases is to observe the cases that occur on the continent in order to describe their characteristics, assess their annual incidence and objectify the secular trend. The aim is to provide annual indicators to help to advise travellers. This surveillance is based on a voluntary network providing standardised informations on the epidemiologic, prophylactic, clinical, parasitologic and therapeutic data. After a noticeable increase between 1987 and 1988, the occurence of the imported malaria cases in France decreased since 1989 then became stable since 1991, between 3,500 and 4,000 cases per year. From one year to another the characteristics of the cases are stable for most of the parameters. However, it is interesting to note: a progressive increase in the ratio of foreigners with a decrease of the median age, the average five days delay between the first symptoms and the diagnostic, the same ratio of severe cases for French people and foreigners, the average time of the stay at the hospital of 4.5 days for non severe malaria cases and the preferential use of halofantrine in first line treatment. The delay of the diagnostic and more precisely the delay of treatment turn-out to be the main factors leading to severe malaria sometimes leading to death. The limited interpretation of data is due to the lack of corresponding denominators required for measuring the rates and density of the incidence as well as the identification of risk factors.