Design of gating system is an important factor to obtain a soundness casting. The soundness casting is indicated by internal shrinkage porosity of commercially pure titanium (CP-Ti). The objective of this research is to get the best gating system between three gating system designs based on the internal shrinkage porosity. Three gating system designs of femoral stem were simulated in investment casting method. The internal shrinkage porosity occurs on the largest modulus of casting. Design of the gating system that has greater ingate dimension on the biggest casting modulus has the least of the internal shrinkage porosity. An experiment is conducted to validate the simulation data. Result of internal shrinkage porosity in the three gating system in simulation compares with the experiment. Based on the comparison, trend of internal shrinkage porosity at the three gating system design in simulation is good agree with the experiment. The results of this study will aid in the elimination of casting defec
