Kinematic viscosities of twelve mixtures made from pentane, hexane, heptane, octane, decane, and carbon dioxide were measured using a rolling ball viscometer. The temperatures ranged from 310 K to 403 It and the pressures from 0.8 MPa to 12 MPa. Kinematic viscosities were converted to absolute viscosities using mixture densities estimated from a modified Rackett equation. Calculated absolute viscosities for the decane + CO2 system were within 0.5% of the values by Cullick and Mathis. All viscosities of hydrocarbon mixtures and hydrocarbons with CO2 could be predicted from the Orbey and Sandler correlation with an average absolute deviation of 4.1%. We found that the Lohrenz, Bray, and Clark viscosity correlation cannot be used to estimate the viscosity of the mixtures containing CO2 with reasonable accuracy.