A thermodynamic micellization model is used in this work to describe asphaltene precipitation from Kuwaiti crude oil. The model is based on asphaltene and resin micelle formation and then destruction by addition of an alkane. A coin-like aggregate of asphaltene surrounded by resin molecules constitutes the micellar phase. The rest of the asphaltene and resin are dissolved in the bulk phase. A group contribution method was used to predict the critical properties for the asphaltenes, resin, and oil. The Peng-Robinson EOS was used to predict the onset point and to perform flash calculations. The onset point and the amount of asphaltene precipitated were measured. Hexane, heptane, octane, and decane with varying volumes and temperatures were used. The model also was tested using high-pressure data. In both cases, the model could describe the experimental data reasonably well with a mean square error of 0.57%.