A relatively simple method of diurnal drift removal from aeromagnetic data which does not require the use of a base station is presented. The underlying assumption is that diurnal drift during flight is a smoothly varying low order polynomial in time. The polynomial coefficients are determined by minimizing residuals at flight-line/tie-line intersections using least squares. This procedure is applied to a conventional sensitivity aeromagnetic survey in northeastern Kansas. The results of the drift determinations compare favorably with independent knowledge of actual drifts such as the magnetic K indices and other measurements.