Nanoparticles of ZnO were synthesized using a sonochemical technique. Sonochemistry arises from an acoustic cavitation phenomenon, that is, the formation, growth and implosive collapse of bubbles in a liquid medium. The ultraviolet photoluminescence (PL) studies of the samples showed a strong PL intensity and a significant blue shift relative to the PL of the bulk. Shifts up to 70 meV were observed and attributed to a confinement effect. Scanning electron microscopy indicated roughly spherical particles, ∼160 nm in diameter. However, nano-platelets and rods were observed in transmission electron micrographs. Preliminary electrical measurements indicated a highly resistive nature of the nanoparticulate material.