A new parameter, pseudo temperature (T-p) is introduced to solve two-phase equilibrium calculations. The resulting T-p-method has a single set of equations to describe different phase regions encountered in vapor-liquid equilibrium (VLE) and liquid-liquid equilibrium (LLE). It does not require a priori the number of phases existing at equilibrium, and involves a minimization problem having a linear objective function subject to nonlinear constraints, which can be solved by a version of successive linear programming method. T-p-method is tested on typical examples for VLE and LLE, and compared with pseudo pressure (P-p) method of Bullard and Biegler [Computers and Chemical Engineering 17, 95-109 (1993)] for VLE. In each example, several operating conditions are considered to cover both single- and two-phase situations. The results show that T-p-method is successful for both VLE and LLE, and that T-p- and P-p-methods are comparable for VLE.