Version 1 of the 21-yr HIRS clear-sky radiance data set has been constructed as a part of the TOVS Radiance Pathfinder data set. These data are the first HIRS radiance data with consistent processing of all the HIRS radiance data. Cloud detection is achieved using a modified form of the ISCCP cloud detection method. Validation of the clear-sky observations with ISCCP AVHRR cloud products indicate good agreement with only 2% of the Pathfinder clear observations found in ISCCP cloud regions. Our conservative cloud detection approach yielded ~13% of the total observations as clear-sky observations. Inter-satellite biases were diagnosed and adjusted using empirical dynamic functions to eliminate transitional jumps in the clear-sky brightness temperature time series. Applications of the clear-sky radiance data for climate studies of water vapor and temperature are discussed.