Propolis extract (PE) is a natural resinous bee product collected by honeybee workers from leaf buds, twigs, trunk wounds and trees. Onychomycosis is a chronic fungal infection of nails, commonly caused by Dermatophyte and Non-Dermatophyte fungi. PE can be a successful treatment candidate as it is known for antimicrobial, antiviral, anticancer, anti-inflammatory and antifungal effects. This study evaluated the antimicrobial effect of PE against different multidrug resistant Gram-positive and Gram-negative bacteria, fungal strains, pests of stored grain, both irradiated and non-irradiated, pathogenic microorganisms and Tribolium castaneum. Effect of different gamma irradiation doses of PE was evaluated at level 1 and 2 kGy doses against Gram-positive Staphylococcus aureus (MMCC21), Gram-negative Escherichia coli (MMCC24) and Pseudomonas aeruoginosa, yeasts Candida albicans M1, Candida albicans M2 and fungi Aspergillus flavus, Aspergillus niger and Trichophyton rubrum. The possible morphological changes that took place on the bacterial, yeasts and fungi cells at level 1 and 2 kGy doses, respectively, were detected using a scanning electron microscope. Results indicated a significant antimicrobial effect of PE against the tested strains. FTIR indicated no significant change on the PE functional group composition; moreover, antibiogram proved no significant changes regarding the antimicrobial activity of irradiated and non-irradiated PE. We also studied the effect of PE, both irradiated and non-irradiated, at level 1 and 2 kGy doses, respectively, on insect pests of stored grain Tribolium castaneum showing different morphological changes.