This paper discusses a procedure to determine the dew and bubble point temperatures and pressures for Mixtures. The procedure uses the fact that isochors change slope when they pass from the single-phase to the two-phase region. A selection of the single- and two-phase region data points results from a statistical analysis. We can determine the phase boundary temperatures and pressures within 0.45% and 0.04%, respectively. We have applied this procedure to determine the temperatures and pressures at the phase boundaries of binary and multicomponent mixtures. The major advantage of the method is the compositions are known from gravimetric construction. (C) 2009 Elsevier B.V. All rights reserved.