X-band and high-frequency EPR spectroscopy was applied to monitor the short-range cation ordering in Ga, Al and Li substituted LiNiO2 with a layered crystal structure. The mixed oxides were obtained by a high-pressure synthesis in an oxygen rich atmosphere. Analysis of the EPR line-width from the X-band experiments together with the values of the g-tensor from the high-frequency EPR experiments permits assesing the local structure of the mixed metal layers. The results obtained show that LiGa (y) Ni1-y O-2, LiAl (y) Ni1-y O-2 and Li1 + x Ni1-x O-2 are homogeneous solid solutions, whereas the Li1 + x Ni1-x-y Al (y) O-2 compositions have rather a complex domain structure of the type (1-a)LiAl (y) Ni1-y O-2.aLi[Li1/3Ni2/3]O-2.