The EPR parameters (D, g(parallel to), g(perpendicular to)) for chromium doped in spinels (MgAl2O4, ZnAl2O4 and ZnGa2O4) have been calculated by diagonalizing the 120 x 120 complete energy matrices for d(3) configuration ion in trigonal ligand field. The Zeeman effect of Cr3+ ion in the trigonally distorted octahedral site of spinels has been studied, suggesting that there is a nonlinear relation between the Delta g (Delta g = g(parallel to) - g(perpendicular to)) and orbital reduction factor k. Both the site symmetries D-3d and C-3v of this impurity have been discussed for the three host lattices, and the local lattice structure around the impurity has also been determined. (c) 2007 Elsevier B.V. All rights reserved.