The self and N 2-broadened linewidths of N 2O have been measured directly in the 10 01-00 00 and 02 0-00 00 bands of N 2O at 297°K with a resolution of 0.03 cm -1. The experimental results are compared with linewidths calculated from Anderson's impact theory as amplified by Tsao and Curnutte. The agreement between experiment and theory is good for both types of broadening. Best-fit values for the quadrupole moments and hard-sphere diameters of N 2O and N 2 are listed and compared with previous values. The best-fit values were used to calculate the N 2O + N 2 linewidths at temperatures of 180°K, 220°K, and 260°K.