ZnO films are multifunctional semiconductor materials which have applications on various scientific fields and known as transparent conducting oxide (TOO). In particular, physical properties of these films can be modified easily by doping with different elements. In this study, undoped and Co doped ZnO films were obtained to investigate and enhance the effect of Co transition metal doping on the properties of ZnO films. Undoped and Co doped ZnO films were deposited onto glass substrates by spay pyrolysis technique. The effect of Co doping on the structural (X-ray diffraction (XRD) studies), morphological (Field Emission Scanning Electron Microscope (FESEM) and Energy Dispersive X-Ray Spectroscopy (EDS) studies) and electrical properties (Hall effect and activation energy measurements) of deposited films was investigated. Structural properties of the films were studied by examined XRD patterns and it was found that all films have polycrystalline structure. XRD studies showed that at the crystallization and grain size prominently changed with Co doping and Co+2 ions locate tetrahedral sites of the ZnO lattice. The Hall effect measurements indicate that the all films have n-type conductivity and mobility values increase with increasing Co doped. Also, we calculated activation and shallow/deep donor like traps energy levels using In sigma - 1000/T graphics. An increase in the Co doping the surface morphology and crystallite size of all the films was clearly changed. FESEM micrographs of the films show that the all Co doped ZnO films have intenser formation and minor particular size. Finally, we investigated and discussed all these results.