Infrared fluxes and cooling rates for several standard model atmospheres, with and without water vapor, carbon dioxide, and ozone, have been calculated using a line-by-line method at 0.01 cm-1 resolution. This study was conducted as part of the Intercomparison of Radiation Codes Used in Climate Models (ICRCCM) where line-by-line calculations are intended to serve as a benchmark for comparing practical codes used in climate models. The sensitivity of the results to the vertical integration scheme and to the model for water vapor continuum absorption is shown. Comparison with similar calculations performed at NOAA/GFDL shows agreement to within 0.5 W m-2 in fluxes at various levels and 0.05 K d-1 in cooling rates. Comparison with a fast, parameterized radiation code used in climate models reveals a worst case difference, when all gases are included, of 3.7 W m-2 in flux; cooling rate differences are 0.1 K d-1 or less when integrated over a substantial layer with point differences as large as 0.3 K d-1. ¿ American Geophysical Union 1991