The state of Campeche ranks first nationally with over 259,000 ha of mangrove coverage. These mangroves are located in the protected area "Laguna de Términos", considered the most important wetland area in the Gulf of Mexico. The main threats to these mangrove forests arise from human activities inland on Atasta Peninsula (INE 1997). These include agriculture, aquaculture, oil production, and population growth. The mangrove forests located in this region are of national ecological and economic importance. We reported the carbon stored in soil and tree biomass, the latter estimated by allometric equations, in a mangrove forest located in the Atasta Peninsula in Campeche, Mexico. We used the allometric equation method because it does not require felling of trees and is therefore useful to estimate temporal changes in forest biomass through subsequent measurements.