The mitotic chromosomes from the gills of the fish Boleophthalmus dussumieri were studied for the induction of chromosomal aberrations after in vivo treatments with three separate antineoplastic antibiotics: Bleomycin (radiomimetic drug), Mitomycin-C (bifunctional alkylating agent) and Doxorubicin (intercalating agent). Fishes were directly exposed to these agents via intramuscular injections. Two separate treatment timings, 4 hours and 24 hours were selected for all antineoplastic treatments. The concentration doses of Bleomycin (150µg and 300µg), Mitomycin-C (1 µg, 2 µg and 4 µg) and Doxorubicin (10 µg, 20 µg and 40 µg) were decided on the basis of the body weight of fishes and earlier laboratory findings. The results revealed dose and time dependent increase in the chromosomal aberrations after treatments with all antineoplastic drugs. The type of aberrations observed include chromatid breaks, acentric fragments, dicentric and ring configurations. The findings add to the fact that the fish Boleophthalmus dussumieri is a suitable cytogenetic model for in vivo detection of potential mutagens.