Early in its mission, the Landsat-7 spacecraft was temporarily in a tandemorbit that drifted across that of the Landsat-5 spacecraft in order to facilitate sensor cross-calibration based on nearly-coincident scenes acquired by the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) and Landsat-5 Thematic Mapper (TM). This paper presents a methodology for radiometric cross-calibration of the solar reflective spectral bands of the Landsat-7 ETM+ and Landsat-5 TM sensors and results based on analysis of two different tandem image pairs for which ground reference data are available. With the well-calibrated ETM+ as a reference, the tandem-based cross-calibrations for the two image pairs yield TM responsivity coefficients that are consistent to each other to within a few percent or better depending on the spectral band. Comparisons with independent methods and results obtained by other groups indicate that the tandem-based cross-calibration is in close agreement with the independent results in spectral bands 1-4 but compares less favourably in bands 5 and 7. The methodology also incorporates adjustments for spectral band differences between the two Landsat sensors. Spectral band difference effects are shown to be more dependent on the surface reflectance spectrum than on atmospheric and illumination conditions. A variety of target types are assessed regarding their suitability for Landsat radiometric cross-calibration in the absence of surface reflectance spectra.