To estimate the cost-effectiveness of the supply of calcium of 1200mg per day from the week 14 of pregnancy to all pregnant women compared to not supplying it to reduce the incidence of preeclampsia. A decision tree was built in TreeAge® with outcome measured in life years gained (LYG) associated to the reduction in maternal deaths. The costs were included from the perspective of the Health System in Colombia. Pharmaceutical costs were obtained from 2008 SISMED (1) and the value of the procedures was calculated by adjusting the values of Tariff Manual ISS 2001 + 30% (2), these values were compared with information of costs supplied by three EPS. All costs are expressed in Colombian pesos of 2010. The discount rate was 0%. It was performed sensitivity univariate and probabilistic analyzes for costs and effectiveness. Compared to no intervention, calcium supplement is a dominant alternative. If the incidence of preeclampsia is lower than 51.7 per 1000 pregnant women or the cost per tablet of calcium of 600 mg is greater than $454, calcium supplement is no longer a cost-effective alternative in Colombia for a threshold of 3 times the GDP per capita in Colombia of 2010 by LYG, equal to $36,143,550. Supply of calcium to all pregnant women from week 14 of gestation is a dominant alternative compared to no intervention, which saves 200 LYG, while it decreases costs in the order of $5,304 million pesos per 100.000 pregnant women.