This paper reports measurements of densities and viscosities for the binary system of 1-methyl-3-octylimidazolium nitrate and different alcohols in the temperature range of (283.15 to 333.15) K. The alcohols are ethanol, 1-propanol, and 1-butanol. The excess molar volume and viscosity deviation are calculated for the above systems, and the Redlich-Kister polynomial equation is used to lit the excess molar volume and viscosity deviation. The excess molar volume and viscosity deviation have negative deviations from ideal solution. The excess molar volumes increase with increasing the alcohol chain length.