The aim of this study was to obtain and characterize ZnO and Co doped ZnO nanoparticles by Microwave assisted method. ZnO plays an important role in many semiconductors technological aspects. In this work, the Co doped ZnO nanoparticles prepared by varying the concentration of Co (CH3COO)2.4H2O. The synthesized nanomaterials were characterized by XRD, FT-IR and SEM with EDX. The XRD patterns showed that ZnO nanoparticles have hexagonal wurtzite structure. The FT-IR study confirms the presence of functional group in ZnO. SEM photographs show that the synthesized pure ZnO and Co doped ZnO were in the shape of nanoneedles and nanospheres. The average size of nanoneedles and nano-spheres were found to be 25-35 nm and 20-30 nm.