ABSTRACT Light and scanning electron microscopic studies of erythrocytes of Channa punctata exposed to two sublethal doses of lindane over a period of 21 days revealed myriads of anomalies. High frequency of micronucleus appeared progressively in the erythrocyte, ranging from 3.8-7.5%, when monitored weekly for 21 d at 0.25 g/L and 1.0-3.0% at 0.025 g/L lindane. Prominent structural anomalies of erythrocytes included abnormal shapes, vacuolation, membrane invagination and disintegration. At higher dose and at later duration, a unique tendency of abnormal cells to stick together was observed. It could be concluded that commercial formulation of lindane could induce genotoxicity and structural anomalies in the erythrocytes of fish.