This survey was conducted between December, 1997 and August, 1998 at the Chantal Biya Maternity Section of the Ebolowa Provincial Hospital, Cameroon. A total of 231 parturient mothers who gave birth to 232 neonates were included in the study. Ninety-five of them (41.1%) took anti-malaria prophylaxis (chloroquine) in the index pregnancy, and 136 (58.9%) did not. Both groups were similar with respect to socio-demographic characteristics except for educational level of the mother, which was significantly higher in the group on prophylaxis (chi 2 = 8.05; df = 2, p = 0.02). The overall prevalence of maternal parasitaemia was 37.2%. The group on chloroquine (TG) experienced a lesser parasitaemia (26.3%) than the non-prophylactic group (CG) (44.9%, odds ratio (OR) = 2.28, CI = 1.24-4.19). The proportion of women with severe parasitaemia (> 4000 parasites/microliter) was also lower in the TG than CG (17.6% vs 7.3%; OR = 2.69, CI = 1.04-7.23). A modest reduction in low birthweight was found in the TG which was not significant (23.4% vs 16.0%; p = 0.16). In conclusion, chloroquine given to prevent malaria in pregnancy was found to be effective in reducing peripheral malaria parasitaemia, but improvement in birthweight could not be demonstrated. Among other factors, impaired biological activity of the drug at the level of the placenta where parasite sequestration frequently occurs might be the explanation. We recommend that further investigation be carried out in the study area to evaluate this finding, and if confirmed, institute appropriate changes in the present policy of chloroquine prophylaxis in pregnancy.