Bioconcentration factors of some carbamates BPMC, carbaryl and carbofuran were determined. The tested fishes were zebrafish (Brachydanio rerio) and red sword tail (Xiphophorus hellieri). The fishes were exposed to 0.05 ppm, 0.01 ppm, 0.50 ppm, one- hundredth concentration of 96-hrs LC_(50) and one-thousandth concentration of 96-hrs LC_(50) and test periods were 3, 5 and 8 days. Obtained results are summerized as follows: In the case of BPMC and carbaryl, BPMC and carbaryl concentration in zebrafish extract and BCFs of BPMC, carbaryl were lower than those of red sword tail, and increased as increasing test concentration. In the case of same experimental concentrations, BPMC concentration in zebrafish extract and BCFs of BPMC were decreased as prolonging test periods. In the case of same experimental periods, carbaryl concentration in zebrafish extract and BCFs of carbaryl were decreased as increasing test concentration, especially dropped at 0.50 ppm. Carbofuran did not bioaccumulate in zebrafish for test periods, in the case of red sword tail, it was impossible to calculate on BCFs data because test concentration of one-hundredth and one-thousandth of 96hrs LC_(50) was under the detecting limit on GC. Test concentration of 0.05 and 0.10 ppm were the same tendency with BPMC and carbaryl. Determined depuration rate conatant were highest on carbofuran, and followed by carbaryl, and BPMC. It is suggested that low BCF of carbofuran is due to its relatively high water solubility and depuration rate, compared to BPMC and carbaryl. Therefore, carbofuran had no little bioconcentration effect on the aquatic ecosystem.