The prediction of cavitation in lubricants is of significance to the design and analysis of hydrodynamic bearings. In this paper, a numerical model for the gaseous cavitation in hydrodynamic lubrication problems is derived based on the cavitation mechanism and origination, which is different from the conventional cavitation conditions. The proposed gaseous cavitation model is then used to calculate the performance of several types of bearings, including a two-axially grooved plain journal bearing, a misaligned journal bearing and parallel thrust bearings with surface textures. The results are validated with experimental data and numerical results calculated by the Half-Sommerfeld, Reynolds, and JFO conditions. The advantage of this new model lies in its accuracy and its independence from the cavitation pressure, which is usually difficult to be accurately defined. Thus this gaseous cavitation model can be useful in the accurate prediction of the cavitation phenomenon and performance of hydrodynamic bearings under steady state.