For management of hemlock woolly adelgid (HWA), two exotic predators, Laricobius nigrinus and Sasajiscymnus tsugae, are currently being mass reared and released into hemlock stands in the eastern United States as part of a classical biological control program. Harmonia axyridis, a polyphagous exotic predator previously released for control of homopteran pests, has spread rapidly across the United States and is now an established predator of HWA. Due to the potential temporal and spatial overlap of these predators, studies were undertaken in 2003 to evaluate competitive interactions among these species in Petri dish bioassays held under simulated natural conditions. Survival, feeding and oviposition rates were compared among single-predator assays and three-predator combinations that contained additional conspecifics or heterospecifics. Survival rates for all species were not significantly affected by conspecifics or heterospecifics. Feeding rates for L. nigrinus and S. tsugae were additive with conspecifics, while H. axyridis had significantly reduced rates. Oviposition rates for S. tsugae were additive with conspecifics, while L. nigrinus and H. axyridis had significantly reduced rates. Feeding and oviposition rates for all species were not significantly affected by heterospecifics. The only significant competitive interactions detected in these assays occurred between conspecifics, while heterospecifics showed non-interference or additive effects. These initial results suggest that these species may be more complementary than competitive.