Nylon 6 polymerization in batch reactors has been assumed to consist of important reactions of ring opening, step growth and polyaddition steps and a set of ordinary differential equations (initial value problem) for the concentrations and moments of the various reacting species has been derived. We have proposed a series solution for these variables in terms of conversion of epsilon-caprolactam. A technique similar to the finite element method for boundary value problems is used to divide the conversion domain into subdomains. The size of these is determined by a convergence criterion and the results determined at the end of conversion domain through sequential computations. This technique of solution involves the evaluation of constant coefficients of the series only and gives comparable results with those of Runge Kutta or Gear’s algorithm (which involves evaluation of functions) in fewer steps. The scheme can easily be implemented on a personal computer and is considerably faster and more efficient.