The purpose of this study was to evaluate the state of knowledge and use of drug in pregnant women diagnosed with malaria at the first prenatal examination. Survey data were conducted of physicians and paramedical staff working the public and private sector in Cotonou, Benin from November 1996 to January 1997. A questionnaire including items on the type of antimalarials used, therapeutic regimens and compliance with the treatment posology and duration guidelines as defined by the WHO and recommended by the National Program against Malaria. A study of informational supports allowed validation of responses obtained during the interview on the day of survey. A random two-degree, stratified sample of 208 prescribers including 109 physicians, 51 midwives, and 48 nurses was interviewed. Data analysis showed that chemoprophylaxis was prescribed by all midwives, 87.5 p. 100 of nurses, and 8.2 p. 100 of physicians. Midwives prescribed this strategy in all pregnant women. For 5.5 p. 100 of physicians and 6.3 p. 100 of nurses, primigravid women were considered as a target group. Chloroquine was the most widely used antimalarial. It was sometimes used in association with proguanil. Of the other drugs used for prevention, quinine was prescribed by 2.4 p. 100 of nurses and 1.1 p. 100 of physicians. The therapeutic regimes and posologies used by the health care workers were not in compliance with the policies of the National Program for Control of Malaria. The findings warrant the creation of an organization to promote consultation and communication between health care authorities and workers.