The study was conducted to assess the gastro-intestinal parasitic infestation in group of calves of different breeds of dairy cattle and buffalo. The faecal samples were collected from animals selected for experiment on 0, 7, 14, 21, 28, 35, 42, 56 day interval at National Dairy Research Institute (NDRI), Karnal, Haryana. The selected animals were examined to determine eggs and oocytes per gram of faecal sample to identify the gastro-intestinal parasites in both control and treatment group provided with normal and treated effluent water respectively in an isolated and well managed hygienic environment. On parasitological investigation the group of animals provided with the treated effluent water did not show any threatened value of gastro-intestinal parasites. At normal value some of the parasites observed were Strongyle specis, Trichuris species and Moniezia species. It was also observed that crossbred cattle were more prone to parasitic infection than the indigenous breed of cattle and buffalo.