Abstract <p>The bending and vibration characteristics have been investigated of the piston pin of internal combustion (IC) engine using where ANSYS 17.2 software. Piston pin is the main component of IC engine’s piston connecting rod assembly; which play a crucial role in transmitting gas force from piston to connecting rod to crankshaft. Design of piston pin needs the awareness of various boundary conditions, loading conditions and developed stress resultant (<i>N</i>_<i>xx</i>, <i>N</i>_<i>yy</i>, <i>N</i>_<i>xy</i>). It is also desires the information of materials, various types of surface treatments to increase its fatigue strength and avoid various modes of failures. Here, bending behavior of piston pin has been studied under mechanical and thermal load conditions after that analyzed the various stresses such as shear stress (τ_<i>xz</i>, τ_<i>yz</i>) and bending stress (σ_<i>xx</i>, σ_<i>yy</i>, σ_<i>xy</i>). Moreover, the empirical formulas for piston pin geometry, clearance, importance of piston pin offset, and complete design procedure of IC engine piston pin is expressed. In this communication the effect of various boundary conditions (fully floating piston pin, semi floating piston pin and stationary piston pin), loading conditions, material properties (Material 1–4), inner cross section of piston pin has been investigated.</p>