The thickness and temperature dependence of in situ grown cobalt thin films on Cr2O3(0 0 0 1) single crystalline substrate has been studied by low energy electron microscopy (LEEM). The LEEM images indicate that growth of thin Co films (⩽5 monolayers) on chromia at 100 K tends to be continuous and flat with suppressed island growth compared to films grown on chromia at room temperature and above (to ~440 K). Low energy electron diffraction indicates that disorder builds and crystallinity of the cobalt thin film decreases with increased film thickness. Compared with cobalt thin films on Al2O3(0 0 0 1) single crystalline substrate, cobalt thin films on Cr2O3(0 0 0 1) show larger magnetic contrast in magnetic force microscopy indicating enhancement of perpendicular anisotropy induced by Cr2O3.