We investigated the effect of seed mass on emergence, seedling survival and growth of Pterocarpus marsupium Roxb., a medium to large, commercially valuable and deciduous tree species. Among the three size classes viz. small(10-12 mm), medium(13-15 mm) and large(16-17 mm), the maximum proportion of seed by number(54.12%) and dry weight(51.87%) was recorded in the medium size seed class. Seed length and seed width were greatest in the large seed class(16.50 mm, 7.33 mm) followed by medium(13.50 mm, 5.60 mm) and small(11.37 mm, 3.66 mm). Similarly, hundred seed weight(100 sw) varied from a maximum of 12.92 g in the large seed class to intermediate 10.95 g in the medium seed class and minimum of 7.02 g in the small seed class. The large seed size showed maximum emergence and shoot length over the medium and small seed class. After six months of growth, significant variations due to seed size were also observed for the growth and dry weight of P. marsupium seedlings. Seedling vigour, expressed in terms of height, collar diameter, number of leaves and dry biomass, was significantly affected by seed class. Seedlings that emerged from large seeds showed better growth and produced heavier seedlings as compared to medium and small seeds. We investigated the effect of seed mass on emergence, seedling survival and growth of Pterocarpus marsupium Roxb., A medium to large, commercially valuable and deciduous tree species. Among the three size classes viz. Small (10-12 mm), medium (13 -15 mm) and large (16-17 mm), the maximum proportion of seed by number (54.12%) and dry weight (51.87%) was recorded in the medium size seed class. Seed length and seed width were greatest in the large seed class (16.50 mm, 7.33 mm) followed by medium (13.50 mm, 5.60 mm) and small (11.37 mm, 3.66 mm). Similarly, hundred seed weight (100 sw) varied from a maximum of 12.92 g in the large seed class to intermediate 10.95 g in the medium seed class and minimum of 7.02 g in the small seed class. The large seed size showed maximum emergence and shoot length over the medium and small seed class. After six months of growth, significant variations due to seed size were also observed for the growth and dry weight of P. marsupium seedlings. Seedling vigour, expres sed in terms of height, collar diameter, number of leaves and dry biomass, was significantly affected by seed class. waslings significantly emerged by seed class as compared to medium and small seeds.