The putative stable structures of trimetallic Au-Pd-Pt clusters are investigated using the Gupta potential. Global optimization of Au8PdnPt30-n, AunPd8Pt30-n, and AunPd30-nPt8 (n=1-29) clusters is performed using adaptive immune optimization algorithm (AIOA). Results show that these global minimum structures can be categorized into five classes, i.e., Marks decahedra, partial Mackay icosahedra, complete truncated octahedra (TO), stacking fault (SF) face centered cubic (FCC), and amorphous motifs. Furthermore, the segregation phenomena of Au, Pd, and Pt atoms in clusters are investigated by the order parameters. The relative stability of the studied clusters is compared through the energetic analysis. (C) 2014 Elsevier B. V. All rights reserved.