After the discovery of multiband superconductivity in MgB2 (Tc = 39.7 K) a number of studies have been made to understand the origin of superconductivity in this compound as well as related compounds. Crystal structure plays an important role in the origin of multiband superconductivity. Recently reported superconductor MgPtSi with orthorhombic honeycomb structure exhibits superconducting transition at Tc = 2.5 K. MgPtSi is a type II superconductor with upper critical field 6.3 kOe and coherence length 230 Å. Upward curvature of Hc2 near TC suggests multiband/multigap superconductivity, which needs further clarification. In this proposal we want to study zero field and transverse field muon spin rotation/relaxation to investigate superconducting properties of MgPtSi using MuSR spectrometer.