Thin films of Co2MnSi have been grown on a-plane sapphire substrates from three elemental targets by do magnetron cosputtering. These films are single phase, have a strong (110) texture, and a, saturation magnetization of 4.95mu(B)/formula unit at 10 K. Films grown at the highest substrate temperature of 715 K showed the lowest resistivity (47 muOmega cm at 4.2 K) and the lowest coercivity (18 Oe). The spin polarization of the transport current was found to be of the order of 54% as determined by point contact Andreev reflection spectroscopy. A decrease in saturation magnetization with a decrease, in film thickness and different transport behavior in thinner films indicate graded disorder in these films grown on nonlattice matched substrates. (C) 2004 American Institute of Physics.