A computational method has been developed for the determination of dissociation constants of acids (and bases). The method is applicable to mono or polybasic acids and, in certain cases, to mixtures of acids. A least-squares treatment is employed, and no simplifying assumptions are made in any of the equations or factors involved. All the available data are utilized, and provision is made for including or calculating activity coefficients. Utilization of the method requires a medium to large size digital computer.