The performance of a Homogeneous Charge Compression Ignition (HCCI) engine fuelled with gasoline by means of a stochastic reactor model is investigated. A zero-dimensional simulation code called Stochastic Reactor Model (SRM) for combustion and convective heat transfer is applied. The gasoline fuel was simulated with a Primary Reference Fuel (PRF) mechanism consisting of 157 species and 1552 reactions. Simulated results are compared with experimental measurements obtained using a Ricardo Hydra HCCI engine. Emissions of CO, CO2 and NOx as a function of the crank angle are considered. In addition, the dependence of performance and emissions on the temperature is investigated. Good qualitative agreement is found between the computations and the available experimental data. The performed numerical simulations predict the same trends; however, quantitative agreement is not very good because the shape of the real piston cannot be modelled in 0-D simulations.