Single crystals of the Ni1+xGexFe2−2xO4 system with 0≤x≤0.41 have been investigated in order to throw some light on the ionic distribution and properties of Ni2+ ions. The properties studied were K1, K2, g factor, and ΔH by means of ferrimagnetic resonance techniques in the temperature range of 4.2° to 393°K. An increase in x results not only in a general decrease in K1 but also in a modification in its temperature dependence. For x≥0.36, K1/M and K1 actually begin decreasing below 80°K. From single‐ion model of anisotropy a linear decrease of K1 with increase in x is predicted, whereas experimentally K1 falls off more rapidly for x≥0.36. To interpret this result an ionic distribution having Ni2+ in A sites is necessary, since from crystal‐field considerations A site Ni2+ ions could contribute a positive K1. Since this contribution is larger at lower temperatures it counteracts the usual increase in ‐K1, thus diminishing the value at 4.2°K. The K1 found for x=0.32 could also be attributed to such A site Ni2+. The above hypothesis is supported by the fact that for a sample with x=0.08 quenched from 1000°C which is known to increase A site Ni2+ concentration, K1 was found to vanish at 170°K. The anomalous variation of g and the sharp increase of ΔH at 4.2°K with x are characteristic of A site Ni2+. Our results indicate the presence of Ni2+ ions in A site for crystals of x≥0.3.