Although the compounds CdCr2S4 and CuCr2S4 are ferromagnetic, solid solutions of the system CdCr2S4-CuCr2S4 with the spinel normal structure show a ferrimagnetic ordering of their magnetic moments with Curie temperatures of about 90 K. For all the samples under investigation one can observe a significant lowering of the saturation magnetic moment in comparison with the theoretical one. Moreover, metamagnetic thresholds were observed at different temperatures. In particular at 250 K the values of the induction of the magnetic field for these thresholds are equal to 0.1 T for x = 0.05, 0.4 T for x = 0.1, 1.1 T for x = 0.15 and 0.4 T for x = 0.2, respectively. The lowering of the saturation magnetic moment and the existence of the metamagnetic thresholds for all the samples under study seem to be connected both with the high defectiveness of the crystal structure and with the mixed valence of the chromium ions. An attempt is made to interpret this fact in terms of the RKKY, double-exchange and superexchange magnetic interactions as well as with the use of the vacancy parameter.