This study seeks to understand and explain the role of isomerism on the structural and magnetic properties of Co-Fe-Pd nanoalloys. To this end, semiempirical Gupta potential was utilized to identify the first three isomers and the global minimum structures of all compositions, and then these isomers were subject to re-optimization by means of the DFT approach. The structural analysis of Co2FenPd17-n (n = 0-17) nanoalloys revealed that Co atoms prefer locations in the inner sites of the nanoalloys. Fe and Pd atoms occupy the surface for both GM structures and isomers. Our general result shows an increase in the total magnetic moment of the nanoalloys but a decrease in the local magnetic moments of the Co and Fe atoms. Another important result is that the local magnetic moment of the Pd atoms is not zero. These results support the idea that the isomerism effect plays a crucial role in structural and magnetic properties.