ABSTRACT Two-phase flow through wellhead chokes, including both critical and subcritical flow and the boundary between them, was studied. Data were gathered for air-water and air-kerosene flows through five choke diameters from 1/4 in. (6.35 mm) to 1/2 in. (12.7 mm), and results were compared to published correlations. A new theoretical model for predicting flow rates and the critical-subcritical flow boundary was tested against these data, as well as data from two published studies. The new model substantially improves the existing methods for predicting choke behavior in two-phase flow.