Abstract The spin reorientation transitions were investigated in Dy 1− x Tm x Fe 10Si 2 ( x=0, 0.2, 0.4, 0.6, 0.8, 1.0) compounds in the temperature range from 77 K to room temperature by means of the initial susceptibility dependencies. An ac bridge of mutual inductance of the Hartshorn type was used. Dy 3+ and Tm 3+ have opposite contributions to the entire magnetic anisotropy. This is manifested by the shifting of the spin reorientation temperatures T SR, when the value of x increases. For x = 0.2 and 0.4 the T SR has a value of 180 and 113 K, respectively. When x=0.6 and 0.8, the T SR lies probably below 77 K and for TmFe 10Si 2 there is no such phenomenon. In DyFe 10Si 2, SR was established at a temperature of T SR=271 K.