The anisotropic part of the spectroscopic splitting tensor g has been determined in a single crystal of triclinic DPPH by means of electron paramagnetic resonance at 4.5 mm wavelength. The method of evaluation of the g-tensor from the experimental data is described. The result after diagonalization is: δg1 = +0.6 × 10 -4, δg2 = = +3.0 × 10 -4, δg3 = -3.6 × 10 -4. The directions of the principal axes of the tensor are given relative to the crystallographic axes. The results are discussed in terms of the spin-orbit coupling.