In this work, a new generalized chemical theory of association is developed and is used to derive the distribution function of associated species formed due to hydrogen bonding in a pure associating fluid. The concepts of conformal solution theory are extended to consider the pure associating fluids, and the derived distribution function is used to obtain the conformal parameters. A general procedure is proposed for computing the parameters of any cubic equation of state based on the conformal solution theory developed in this work. As an example, the parameters of van der Waals equation of state are obtained. The PVT calculations for three associating fluids (water, ammonia, and methanol) substantiate the effectiveness of the proposed approach.