Use of different pesticides in the agriculture sector, in order to boost crop yield within a short time period and low labor, has been tremendously increased since the last decade. Pesticide use has elevated crop yield but has produced a number of pronounced problems regarding environmental and health safety. The continuously deteriorating toxicological effects of these pesticides are not only hazardous to humans and land animals but also to economically important aquatic organisms such as fish. One of these extensively used pesticides is an organochlorine insecticide, endosulfan. Experiments conducted in the past have shown the deleterious effects of endosulfan on different aspects of various fish species but its genetic toxicity has not been well studied. The present study was conducted to diagnose the DNA damage induced by endosulfan in peripheral blood erythrocytes of an economically important teleost fish rohu, Labeo rohita (Hamilton, 1822) using comet assay. The fish were exposed to three different sub lethal concentrations (1, 1.5 and 2 µg L^-1) of endosulfan for 7, 14, 21 and 28 days. Rohu showed different extents of DNA damage at different concentrations and time, in terms of genetic damage index (GDI), percentage of damaged cells (% damaged cell) and cumulative tail length (µm) of the comets. Increase in DNA damage was observed to be concentration and time-dependent. The current study revealed the severe genotoxic effects of endosulfan in rohu, Labeo rohita. Therefore its discriminate use should be avoided as it can contribute to the decline of rohu in natural habitats. Also it should be considered as a hazardous threat for human consumption.