The new modified forms of the Wilsou and the NRTL equations of heat of mixiug data were developed, whose application can be extended to isobaric binary VLE predictions. That was obtained assuming that the two Wilson and NRTL parameters are linear functions of teınpe- rature. Both equations give sufficicnt predictions for systems with max heats of mixing less then 130 cal/ g. mol. Howevcr, the Wilson equation is incapable to describe the heat of mixing data for the system with large heats of mixing, the NRTL equation can overcome this problem, but the quality of the VLE predictions is stili poor.