The field experiments were carried out at Experimental farm of Nalanda College of Horticulture, Noorsarai, Bihar, India during Rabi seasons of 2018 to 2019 to identify the effect of different pollinators on onion seed production. The pollinators recorded in the present investigation observed that pollination activity of Hymenopteran insects was most abundant followed by Diptera, Lepidoptera, Coleoptera, Hemiptera and Orthoptera. All the four Apis species viz.,- A. mellifera, A. florae, A. dorsata and A. cerena were recorded as top workers on onion umbels as pollen and nectar gatherers. The data recorded that the different modes of pollination viz., caged without insect pollinators (SP), caged with A. mellifera (Bee pollination-BP), and open to all insect (Natural Pollination-OP), the most effective mode proved to be natural pollinated (OP) that maximum number of seed per umbel (1246), 1000 seed weight (3.45g), yield per m2 area (102.14g) and yield per hectare (1021kg) followed by Bee pollinated (925), (3.05), (82.09) and (8.20) and Self pollinated as (107), (1.90), (21) and (2.10) respectively. The percentage increased was more in open pollinated (386.19) followed by Bee pollinated (290.48) over without insect pollinated plot.