The viscosities of binary mixtures of cyclohexane and n-hexadecane at high pressures were measured for six different compositions with an electromagnetic viscometer in the range of (6.90 to 62.05) MPa at temperatures varying from (318.15 to 413.15) K, extending the data of Tanaka et al. with a vibrating crystal viscometer and that of Wakeham and co-workers utilizing a vibrating wire viscometer, for higher temperatures. The data were correlated with the molar additive mixing rule using temperature-dependent Gaussian functions in pressure for pure component viscosities. At higher temperatures, the curvature of the viscosity-pressure function changes significantly with composition for this asymmetric mixture.