Seismic lines from different vintages frequently mis-tie where they intersect. The mis-ties may stem from different amplitudes, a shift in time, or different wavelet character. We can correct these mis-ties to a great extent by applying a scale factor, a static time shift, and a phase rotation to one of the lines.We describe algorithms to compute the amplitude, time, and phase differences at each intersection among a series of 2-D seismic lines. We can then use an iterative least-squares technique to derive optimal mis-tie corrections for each line. We include a necessary modification of the least-squares technique for the nonlinear phase data. The various algorithms are stable, fast, and accurate. We have used them in conjunction with an interactive workstation seismic interpretation program for five years. The scalar mis-tie corrections greatly enhance the consistency of the seismic data.We show the results of the mis-tie package applied to a 20-line survey consisting of five vintages of seismic data. The resulting mis-tie corrections significantly improve the fit between the 20 lines.