Bimetallic platinum-based transition-metal (PtTM, TM = Fe, Co, Ni, Cu, and Zn) nanoclusters are potential candidates to improve and reduce the cost of Pt-based catalysts, however, our current understanding of the binary PtTM nanoclusters is far from satis- factory compared with binary surfaces. In this work, we report a density functional the- ory investigation of the structural, energetic, and electronic properties of binary PtTM nanoclusters employing 55-atoms model systems (PtnTM(55-n)). We found that the formation of the binary PtTM nanoclusters are ener- getically favorable for all systems and compositions. Except small deviations at the ICO core-shell configuration (Pt42 TM13 ), we found that the excess ention) and the chemical order parameter follows nearly a parabolic behavior as a function of the Pt concentration with a minimum at nearly 50 % for both properties and all systems. From our structural analysis, the difference in the atomic size of the Pt and TM chemical species contribute to increase the segregation, which reaches its maximum for the ICO core-shell configuration, and hence, an ideal homogeneous distribution cannot be reached. Except for PtZn, we found that the equilibrium bond lengths from TM55 increases almost linearly by replacing TM by Pt atoms, and hence, it follows approximately the Vegard’s law. We found that the center of gravity of the occupied d-states of the surface atoms changes almost linearly for PtCo, PtNi, and PtZn, and hence, a particular d-band center can be tunned by controlling the composition of the chemical species, while there are deviations from the linear behavior for PtFe and PtCu.