Effect of different modes of pollination, viz.,without insect pollination, hand-pollination, open-pollination and open-pollination + hand-pollination on yield parameters of 4 summer squash (Cucurbita pepoL.) hybrids viz., Parikrama, Chandra, Chamatkar and Gold Queenwas studied at Research Farm of the Department of Entomology, CCS Haryana Agricultural University, Hisar during 2014. Irrespective of different hybrids, the treatment open-pollination + hand-pollination and open-pollination produced the maximum number of fruits per plant (73.50 and 71.25%, respectively) followed by hand-pollination (59.08%) and no fruits were observed (0% fruit set) under without insect pollination treatment. Average fruit weight, fruit polar diameter and equatorial diameter were maximum (135.30 g, 3.74 cm and 3.47 cm, respectively) under open-pollination + hand-pollination, while these were minimum (94.81 cm, 2.14cm and 2.48 cm, respectively) under hand-pollination treatment. These results indicate that honey bees as well as wild pollinators are utmost essential for pollination of summer squash flowers and thus increasing fruit size and yield. Therefore pollinators conservation practices should be followed in summer squash growing ar-eas for getting higher yield and returns.