This paper presents structural, magnetic and transport property measurements carried out on as deposited as well as annealed Co (400 angstrom) thin films. The magnetization measurements carried out using a magneto-optical Kerr effect (MOKE) technique show large increases in coercivity and saturation field values with annealing of the samples at higher temperatures. However, corresponding resistivity measurements show a gradual decrease in resistivity and drops to minimum at 500 degrees C. Observed magnetization and resistivity behavior is mainly attributed to (i) change in crystal structure from hcp to fee; (ii) increase in grain size; and (iii) stress relaxation due to the annealing treatment as revealed by x-ray diffraction measurements. (c) 2006 American Vacuum Society.