The present work aims to study the changes in protein profile of haemolymph of bacterial-challenged worker honey bee, Apis mellifera. To achieve this task, worker honey bees were challenged with the gram positive bacteria, Streptococcus sanguinis, and/or the gram negative bacteria, Klebsiella pneumoniae using micro-syringe. Haemolymph was collected at four hours interval for seventy two hours post-infection from both bacterial-challenged insects and control, as well. Total soluble protein of haemolymph was extracted and separated using native and SDS-PAGE at different intervals. Results of native and SDS-PAGE demonstrated differences in the haemolymph protein banding patterns of immunized honey bee workers as compared to control. Molecular weights of the separated proteins were calculated from SDS-PAGE. Bacterial challenge induced many proteins of different molecular weights (116-14 KD) as compared to control.