Here we present a new approach for estimating the slowness vector of incident P-waves from records of a single or an array of 3-component (3C) seismometers. The slowness vector is extracted by using a Maximum Likelihood (ML) inversion scheme where the signal model incorporates the transfer function of the layered crust beneath the receivers. The unknown time function of the incident plane wave is excluded from the inversion. In the case of array observations both polarization and moveout times are utilized. The scheme was tested on records of NORESS 3-component stations from teleseismic and local events and the obtained slowness estimates are closer to the expected values than estimates derived by conventional methods. ¿ American Geophysical Union 1991