Bitter gourd (Momordica charantia) is a cross-pollinated crop, so needs bees for fruit set. An experiment was conducted at the Entomological Research Farm, CCS Haryana Agricultural University, Hisar during the rainy season of 2009. Observations were taken throughout the blooming period. A total of nine bee species of three families (Apidae, Halictidae and Megachilidae) were recorded as visitors to bitter gourd flowers. Amongst these, Halictus sp., Megachile sp. and Apis dorsata Fabricius were found to be the most frequent visitors. The abundance of Halictus sp. was highest, followed by Megachile sp. and A. dorsata. Irrespective of species, the bee population was maximum at 0800-1000 h of the day. Based on pollination index (Number of loose pollen grains sticking on the body of bee x abundance x foraging rate), A. dorsata was the most efficient pollinator of bitter gourd, followed by Halictus sp. and Megachile sp.