Nanoparticles of Co 2+ and Mn 2+ codoped ZnO have been obtained by the sonochemical method. The nanoparticles were characterized by x-ray diffraction, scanning electron microscopy, ultraviolet-visible spectroscopy, N 2 adsorption by the Brunauer-Emmett-Teller method and electrical measurements by current-voltage curves. The photocatalytic property was analyzed against the methylene blue (MB) dye and the antimicrobial properties were estimated against the Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria by the disc diffusion method. The results indicate that ZnO powders were obtained without the formation of secondary phases, with initial nanoplate morphology, which is lost with doping. The codoped sample had a five-fold higher electrical response, reduced the MB dye concentration by 10% and increased the inhibition halo by 3 cm and 4 cm against S. aureus and E. coli, respectively, compared to bare ZnO.