Summary: This paper introduces a novel type of convex function known as the refined modified \((h, m)\)-convex function, which is a generalization of the traditional \((h, m)\)-convex function. We establish Hadamard-type inequalities for this new definition by utilizing the Caputo \(k\)-fractional derivative. Specifically, we derive two integral identities that involve the nth order derivatives of given functions and use them to prove the estimation of Hadamard-type inequalities for the Caputo \(k\)-fractional derivatives of refined modified \((h, m)\)-convex functions. The results obtained in this research demonstrate the versatility of the refined modified \((h, m)\)-convex function and the usefulness of Caputo \(k\)-fractional derivatives in establishing important inequalities. Our work contributes to the existing body of knowledge on convex functions and offers insights into the applications of fractional calculus in mathematical analysis. The research findings have the potential to pave the way for future studies in the area of convex functions and fractional calculus, as well as in other areas of mathematical research.