The objective of this study was to quantify carbon pools in natural forests and pasture areas, under three different soils type. The experiment took place in areas from Faculdade de Ciências Agronômicas/UNESP, Botucatu, SP, Brazil. Soil samples were collected at different depths (0 to 90 cm) and at different seasons (summer and winter). Results showed carbon content reduced with soil depth and from forest to pasture areas in all sites. Sites 1 and 3, in initial process of succession, presented higher carbon content at winter. Although carbon content is higher in the first 10 cm soil depth, forest soil accumulated more than 120 Mg ha-1 along the profile (0 - 90 cm), showing high capacity to stock carbon and an important role of forests in carbon sequestration.