This paper reports numerical investigations performed to simulate the free oscillations of floating body in calm water using Improved Meshless Local Petrov-Galerkin method based on Rankine Source function (IMLPG_R). The IMLPG_R method is a mesh-free method for solving the interaction between floating bodies and waves based on the viscous fluid theory. The pressure at each time step is estimated by solving the Pressure Poisson Equation, which is derived from the Navier-Stokes Equation using the fractional step method. The forces and moments acting on the floating body are calculated by integrating the pressure on the body surface. Then using Newton's Second law, the translational and rotational motions of floating body are evaluated. The free heave response and roll response of floating body in calm water are numerically simulated. Copyright © 2018 by the International Society of Offshore and Polar Engineers (ISOPE)