In the present study, a dynamic model is developed for the calculation of the molecular weight and long chain branching distributions in a continuous solution metallocene-catalyzed ethylene polymerization reactor. The model is based on the fractionation of the total polymer chain population into a number of classes, each one representing polymer chains having the same long chain branching content. According to the proposed method, dynamic balance equations are derived for the leading moments of each class of polymer chains as well as for the moments of the overall "live", saturated and unsaturated "dead" polymer chain distributions. A two-parameter Schultz-Flory distribution is used to reconstruct the molecular weight distribution (MWD) of individual classes of polymer chains in terms of their leading moments. The overall MWD is calculated by the weighted sum of all class molecular weight distributions. Simulation results are presented to demonstrate the predictive capabilities of the present model and a parametric study is carried out to analyze the effect of the rate constant for long chain branching formation, k(pLCB), on the MWD and the average molecular properties of the polymer. The effects of chain transfer agent concentration and reactor mean residence time on the molecular weight and long chain branching distributions of polyethylene are also studied.