The comparative toxic effects of α-cypermethrin, emamectin benzoate andimidacloprid were examined on honey bees (Apis mellifera L.). Separate groups of bee workers (A. mellifera) were left for 24 and 96hr to feed on 50% sucrose solution containing different concentrations of the tested insecticides, and the lethal concentration of each insecticide that caused 50% mortality (LC₅₀) was estimated. The inhibitory effects of different selected concentrations (¼ LC₅₀, ½ LC₅₀ and LC₅₀) on AChE, antioxidant enzymes activities (as environmental biomarkers) and the level of Malondialdehyde (MDA) (as an indicator for lipid peroxidation were determined in vivo after 24hr in head (for AChE) and in midgut (for antioxidant enzymes and MDA level) of surviving bees obtained after treatments with the insecticides to explore the possible effects of these compounds. Results indicated that exposure to emamectin benzoate showed toxicity to honey bees with LC₅₀ value of 0.275mg/l, followed by α-cypermethrin (LC₅₀= 5.4mg/l) while imidacloprid was the least toxic tested compound (LC₅₀=24.97mg/l). Alpha (α) cypermethrin at the tested concentrations of 1.6, 2.7 and 5.4mg/l inhibited the activity of AChE in honey bees workers. Also, imidacloprid at 6.2, 12.5 and 24.97mg/l caused inhibition of AChE activity. On the other hand, emamectin benzoate at the concentrations of 0.07, 0.14 and 0.275mg/l caused high activation of AChE. In addition, the toxic effects of the tested compounds on antioxidant enzymes activities indicated that all compounds caused activation of these enzymes. Moreover, there was a decrease in the level of Malondialdehyde in the case of α-cypermethrin and imidacloprid, while emamectin benzoate elevated the level of MDA in honey bees. This suggests the use of AChE and antioxidant enzymes as environmental biomarkers for the assessment of the toxic effect of the tested insecticides on ecosystem health. It might allow the detection of early biological change, which may result in long-term physiological disturbances.