The present invention provides: (a) a method for producing a poly(arylene sulfide)(PAS) resin composition: (b) a PAS resin composition produced by the inventive resin composition production method; (c) a method which utilizes the inventive PAS resin composition in the production of a continuous fiber-reinforced composite; and (d) a PAS composite produced by the inventive composite production method. The PAS resin composition produced by the inventive resin composition production method comprises a crystallizable arylene sulfide polymer and a nucleating agent. The nucleating agent is admixed with the crystallizable arylene sulfide polymer by adding said nucleating agent to the polymerization reaction system. The inventive PAS resin composition solidifies to a fine-grained crystalline morphology and is well suited for use in the production of continuous fiber-reinforced composites, molded articles, and other products.