Seasonal variation in the diet of the fugivorous bat, Rousettus leschenaulti of the Lengteng Wildlife Sanctuary was studied from January 2013 to December 2013. The diet of the frugivorous bats, R. leschenaulti was evaluated by four methods: analysis of the discarded plant parts like fruits, flowers, leaves, seeds and bolus; analysis of pollens attached to the body of bats; the field observation on feeding behaviour of bats, and the analysis of faecal matter to identify the undigested seeds. These bats consumed the fruits of 34 plant species, leaves of 6 plant species and, flowers, nectars, and pollens of 5 plant species. They consumed fruits exclusively from May to September, but during the remaining months, they supplemented their diet with other plant parts. Leaves, flowers, nectars and pollens were consumed during seven months, i.e., from January to April, and October to December, when the fruit resources were depleted or not available in sufficient quantity in the sanctuary.