Abstract The absolute calibration, linearity, and uniformity characteristics of a CNES spherical and a NASA hemispherical large aperture integrating calibration sources were compared at MATRA, Toulouse, France, in October 1987, using the SPOT-2 satellite instruments. An important output of the experiment is the SPOT-2 absolute calibration coefficients obtained by using the two sources each with their own calibration. The paper describes the results and a tentative error budget to explain the 4–8% range discrepancies. The linearity of the two sources has been investigated by plotting as a function of radiance the apparent calibration of SPOT-2 when seen by a given source (sphere or hemisphere) with a varying number of lamps alight in the source. It is also possible to infer to some extent the SPOT-2 nonlinearity by using the data of nonlinearity of the two sources as seen by a commercial laboratory spectroradiometer. The angular uniformity of the sources in the field of view of the SPOT-2 instrument (4°) is tested by a comparison of the normalized responses of the CCD detectors in the focal plane when illuminated by the sphere and by the hemisphere. This comparison shows virtually no difference between the responses, from which it is inferred that both sources have an excellent uniformity over a 4° field of view.