A rigorous solution to a model of radical depolymerization is presented. The model includes random chain scission, depropagation, radical transfer, and first-order radical termination. The evolution of the molecular weight distribution in the course of depolymerization has been determined under the condition that the initial polymer is characterized by Flory's distribution. The kinetic equations consider the presence of chains with two radicalized ends, which are usually neglected. The commonly used simplifying assumption of the steady-state radical concentration is not employed, and this makes the obtained results valid at any ratios between the rate constants. The predictions of the steady-state approximation are compared to those of the rigorous approach in the case of depolymerization accompanied by volatilization of monomeric species. (C) 2003 Wiley Periodicals, Inc.