Revegetation is a very important part of reclamation program of mined land, partly because of its potential to store C. This research was aimed to estimate C stock of two tropical legume plantations of different ages under reclaimed mined lands. The two tree legume species were mangium (Acacia mangium) and sengon (Paraserianthes falcataria) of 4, 8, and 12 yrs of age. Observation plots of 50 x 50 m were established under each stand and age. Tree whole plant samples from each plot were destructively taken from each stand and age. The fallen trees were separated into stems, branches & twigs, leaves, and roots, then weighed and dried in the oven to gain plant dry weights. Sub-samples of about 200-g dry weight of each plant part were taken and grounded for C analyses. Data of the calculated C showed that the amounts of total C stored varied with species and age. In general sengon stored much more C than mangium, and the stored C increased significantly with age. The increase with aging, however, was significantly much higher in sengon. Total C stored by 4, 8, and 12 yr-sengon trees were 10.35, 155.05, and 489.63 kg tree^-1, respectively, while those stored by mangium of the same ages were 21.66, 47.72, and 112.27 kg C tree^-1, respectively. Interestingly, the majority of C was stored in the steams of both tree species. The implication of this finding is that sengon is preferred than mangium for reclamation program.