Exposure of Calcium phosphate affected the entomopathogenic nematode Heterorhabditis sp. differently. Survival, infectivity and penetration efficiency of Heterorhabditis sp. ((HPS1, HPS2 and HPS3) were affected by Calcium phosphate. At medium concentration (1M) of Calcium phosphate the affect on survival of Heterorhabditis sp (HPS1, HPS2 and HPS3) were 68.3, 30.2 and 33.5%, respectively. Calcium phosphate (0.2M and 2M) were less effective on survival of the three nematode strains (8.02to12.2%) and ( 2.02 to 14.6%), respectively. Entomopathogenic nematodes (HPS2) when used alone or mixed by low concentration (0.2M) unaffected on infectivity of Galleria mellonella (100%), but medium concentration affected the infectivity of G. mellonella . The penetration rate of nematode alone was better than from the nematode mixed with Calcium phosphate. Calcium phosphate at three concentrations also reduced the penetration efficiency of nematodes (HPS1, HPS2 and HPS3) (29.8, 32.7 and 27.9%) for three concentrations, respectively.