This study was carried out in 1998 to assess attitudes and practices with regard to prophylaxis for malaria in expatriate families with children attending French and international schools in Abidjan, Cote d'Ivoire. Data was obtained for a total of 4990 subjects of various ages. Forty point five percent of families reported use of drug prophylaxis. Use of drug prophylaxis decreased with age (69.2 p. 100 up to 1 year versus 34.5 p. 100 after 15 years). The proportion of subjects using bednets was 7.5 p. 100. Some subjects reported use of ineffective or dangerous substances such as pyrimethamin alone (17.5 p. 100) or amodiaquin. The incidence of reported malarial attacks increased in function of the length of stay in the country (50 p. 100 after 15 years). The most effective method of drug prophylaxis appeared to be a chloroquin and proguanil combination which was used by 25.4 p. 100 of subjects. The incidence of malarial attacks in subjects using this combination was 20.8 p. 100 as compared to 43.2 p. 100 in subjects using no drug prophylaxis. Forty-seven percent of the study population reported use of other preventive measures but none correlated with a decrease in the number of malaria attacks. Information concerning preventive measures is readily available but sometimes contradictory. Information provided locally seems to be the most effective but not always the best adapted. To increase the awareness among expatriates, it will be necessary to provide more accurate information about effective preventive measures especially regarding bed nets and drugs. The suggested optimal duration of chemoprophylaxis is unclear but this study shows that there is no difference between those that do or do not use it when the length of stay exceeds ten years.