This study was made to compare carbon and nitrogen accumulation of aboveground, A₀-layer and soil between subtropical forests growing in limestone and silicate habitats in the northern part of Okinawa Island. Aboveground biomass in the limestone and the silicate forests was respectively estimated to be 141.2 t ha^-1 and 158.0 t ha^-1. C and N contents of stem and leaf in the limestone forest were higher than those in the silicate forest. However, C and N accumulation of aboveground in the limestone forest were lower than those in the silicate forest because of lower biomass in the limestone forest. Mass of A₀-layer in the limestone forest (5.6 t ha^-1) was higher than that in the silicate forest (4.3 t ha^-1). There was no significant difference in A₀-layer C and N contents between the two forests. However, C and N accumulation of A₀-layer in the limestone forest were higher than that in the silicate forest. Soil C accumulation from soil surface to 100 cm deep in the limestone forest (119.6 t ha^-1) was much lower than that in the silicate forest (187.0 t ha^-1). However, soil N accumulation which was 14.0 t ha^-1 and 15.4 t ha^-1 respectively in the limestone and the silicate forest, was similar.