Introduction: Metal Oxide Nanoparticles can show distinctive physical and chemical properties due to their limited size. Metal oxide nanoparticles have been a hotspot in nanomaterials research due to the wide range of application in the pharmaceutical, biomedical, electronics, optics, energy storage industry and catalysis. Aim: To prepare the metal oxide nanoparticles of copper, nickel and zinc by the sol-gel method and evaluate their antibacterial and antifungal activity against the selected gram-positive, gram-negative bacterial strains and fungal strains respectively. Methodology: Three different variants of each metal oxide nanoparticles were obtained by employing an annellation of the In-situ generated metal hydroxide at temperatures 250, 450 and 6500C. Streptomycin (100__ampersandsignmu;g/ml) and Nystatin (10__ampersandsignmu;g/ml) were employed as reference standards for the evaluation of the antimicrobial and antifungal activity of the different variants of each metal oxide nanoparticles. Results: The experiments of antimicrobial assay revealed that the CuO nanoparticles possess the highest antibacterial activ ity than the remaining metal oxide nanoparticles. ZnO and NiOnanoparticles have displayed better activity against the fungal strains. Relatively the nanoparticles produced at 450 and 6500C temperatures displayed superior antimicrobial activity than the pure metal oxides and nanoparticles produced at 2500C. Conclusion: The CuO nanoparticles calcinated at higher temperatures like 450, and 6500C were displaying higher antimicrobial activity relative to the pure metal oxides and those calcinated at 2500C.