A new and efficient method for phase equilibrium calculations using cubic equations of state (EOS) has been developed. The reduced flash technique presented here takes into account non-zero binary interaction coefficients (BIC's), and requires the iterative correction of a reduced number of independent variables (2m+3, where m is the number of components with non-zero BIC's), irrespective of the number of components in the mixture. A new extrapolation procedure, called the Direct Reduced Flash Calculation (DRFC) is formulated. Calculations performed for several hydrocarbon mixtures with emphasis to the near-critical region prove the robustness and the efficiency of the proposed method.