The fabrication of Co doped rutile thin films on α-Al 2O3 (10-12) substrates by laser molecular beam epitaxy was discussed. It was shown that the rutile thin films were (101) oriented and have smooth surfaces with no impurity phases by using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The contribution of oxidized (Co2+) and metallic (Co0) cobalt to the ferromagnetism was also discussed. The observed ferromagnetism was uniform and was related to the electron band structure of TiO2 rutile, according to magnetic circular dichroism studies. Characterization of Co doped rutile thin films showed that Co in rutile TiO2 takes two valence states.