The book has been written on endoparasites of of Indian major carp, Labeo rohita. There different sites were selected and prevalence of endoparasites was explored. Mainly nematodes and trematodes were present in the gut and liver. Intensity was much higher in the gut than liver. In addition to that effect of these parasites on vital organs like gut and liver was also explored. These parasites have drastic effect on these two organs on their cellular level.