Food and feeding habits of otters were studied in Corbett Tiger Reserve between November 2001 and February 2004. Diet of otters is described from the analysis of fresh scats collected from three different river stretches viz. Ramganga, Mandal and Palain, covering 100 km stretch of the study area. The data is used to assess seasonal differences in predation and to compare this with any changes in the availability of prey. The structure and numbers of the fish assemblage were evaluated using fish traps; gill netting was carried out only to supplement trapping results. Prey remains from scats were identified by the comparison of body parts with a reference collection of appropriate prey species. A total of 16 fish species belonging to six families were identified during sampling. Catch per unit effort (CPUE) was calculated to determine the fish availability for winter and summer seasons. For both the seasons, River Ramganga recorded a maximum of CPUE while River Palain recorded minimum. Among the seven food categories identified, fish (83.92%) was the most frequently occurring food item and also formed the bulk of the otter’s diet. Crabs (9.79%) and frogs (4.19%) formed an important subsidiary food item. The number of prey species of fish in a scat varied from 1 to 5. The most frequently occurring was Glyptothorax pectinopterus (29.3%), while Tor putitora (9.7%) was the least occurring. Food resource availability plays an important role in the presence of otters in the reserve and the otter population consistency could well be related to preferred prey abundance. The effects of the dam construction on otter feeding behavior are discussed and the conservation implications addressed.