Author Institution: Ames Laboratory-ERDA and Department of Chemistry, Iowa State UniversitySelf-broadened and foreign-gas (N2β and O2β) - broadened linewidths of O3β at 300βK for a wide range of quantum numbers J and Kβ1β, for both type A and type B bands, have been calculated using the recent formulation by Yamamoto and Aoki for asymmetric top molecules in the framework of Anderson-Tsao-Curnutte theory of line broadening. The computer program written for these calculations is quite general and can be used for linewidth computations for other asymmetric top molecules. The values for the quadrupole moment tensor elements of O3β have been taken from Rothenberg and Schaefer III. Computed values for linewidths are in good agreement with all of the available experimental data on O3β linewidths. Air-broadened linewidths of O3β at 200βK have also been calculated