The kinetics of the luminescence concentration depolarization of molecules in a medium is studied theoretically. It is shown that the concentration depolarization kinetics is well described by a stretched exponential function of time, r(t)/r0 ≈ exp[−b(t/τ)β], where r(t) and r0 are the luminescence anisotropy values at time moments t and t = 0, respectively. The parameters b and β allow the determinnation of the penetration depth of the molecules in the medium.