The experimental densities rho, and viscosities eta, of binary mixtures of 2-pyrrolidone with butanol isomers: 1-butanol, 2-methyl-l-propanol, 2-butanol, and 2-methyl-2-propanol have been measured at T = (293.15, 298.15, and 303.15) K and atmospheric pressure over the whole mole fraction range. From these data, excess molar volumes, V(E), and viscosity deviations, eta, have been calculated at various temperatures. Both excess molar volumes and viscosity deviations are negative for all investigated systems. The excess molar enthalpies, H(E), measured at 298.15 K and at atmospheric pressure for the four systems are positive over the whole mole fraction range. The experimental results have been correlated using Redlich-Kister polynomial equation, and parameters from least-squares analysis have been reported.