SUMMARY Pre-eclampsia/eclampsia is a major cause of maternal morbidity and mortality world-wide and especially in the developing countries. Strategies to reduce the risk of pre-eclampsia continue to stimulate worldwide interest. Calcium supplementation has been suggested to reduce the incidence of preeclampsia. However, studies on the relationship of calcium and pre-eclampsia from developing countries have been scanty. This case –controlled study sort to determine and compare the serum calcium levels in normal pregnant patients and in pre-eclamptic patients in Benin-city. Eighty-two patients were recruited, made up of 41 cases and 41 controls. The pre-eclamptics had a lower mean serum calcium level of 1.76 ± 0.43 mM/L, while the mean serum calcium level of the normotensives was 1.91± 0.31 mM/L. The observed difference was statistically significant p<0.05. Furthermore, the serum calcium level of the normotensives pregnant women in Benin was found to be lower compared to that of pregnant women reported in the literature. The association of a lower serum calcium level and pre-eclampsia in this study could suggest a possible beneficial effect of calcium supplementation during pregnancy in our environment.