The linear and the nonlinear radial propagation of drift wave energy in an inhomogeneous plasma is studied numerically based on model equations of Hasegawa–Mima for the collisionless case and of Hasegawa–Wakatani–Taniuti–Kaw for the collisional case. In the linear regime the drift wave energy spreads out symmetrically along the direction of inhomogeneity with a finite group velocity. In the nonlinear regime for the collisionless case the radially located drift wave energy is found to propagate in the radial direction. However, the direction of propagation depends on the initial parameters of the pulse. In the collisional case the energy is found to propagate in the direction of decreasing resistivity. These results provide qualitative insights into the phenomenon of drift wave turbulence observed in tokamak plasmas.