Molecular weight averages and molecular weight distribution (MWD) of polymers formed via nonterminating polymerization in a series of continuous stirred tank reactors (CSTRs) under conditions of chain transfer reactions are considered theoretically. For chain transfer to solvent, the temperature regime is defined which provides the highest <(P)over bar (n)> at the outlet of the series. Chain transfer to polymer is shown to be the possible reason for gel formation in the first reactor. Critical conditions for gel formation are derived.