This data set is a partial collection of spectra in digital form from the Mariner 6 and 7 Infrared Spectrometer experiments. All Mars and near-Mars sky spectra are included here, as well as some relevant laboratory spectra of blackbody sources. Lacking are the inflight spectra of reference targets including the wavelength calibration spectra. The IRS data are arranged as a single set of 512 spectra calibration spectra, followed by 122 Mariner 6 spectra, followed by 354 Mariner 7 spectra. The latter set is larger because the long-wavelength channel detector system failed on Mariner 6. These spectra are presented here in raw form, as originally supplied to the NSSDC on microfiche. Note that the geometry information in the spectrum headers was revised by the producer in 1984 to account for the revision in the location of the Mars pole following Mariner 9 observations.