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The magnetotransport properties of CrO2 films down to single-grain sizes have been investigated. The magnetoresistance of highly grain oriented CrO2 (100) films, deposited onto TiO2 (100) substrates using a high pressure cell, has been measured in the temperature range of 1.5–300 K and in magnetic fields up to 6 T. The difference in the magnetoresistance at the low temperature of these samples is related to the value of the residual resistance ratio (RRR = R273 K/R4.2 K) of the samples. The negative magnetoresistance observed in some of these films is likely due to defects (disorder) in the CrO2 crystal. We observed a large positive longitudinal magnetoresistance in the CrO2 sample when it was measured with the current perpendicular to thec axis. The nature of the large value of the longitudinal magnetoresistance may be related to the complex configuration of the Fermi surface of CrO2.