A mathematical model of a hot air anti-icing system and its implementation in the ice accretion simulation code CANICEarepresented.Theicing codeisusedto predictthesurfacetemperatureandtheamount ofrunbackwater for given atmospheric conditions and heat e ux distribution from an anti-icing device. The external boundary layer is modeled with an integral method. Velocity and temperature distribution in the water e lm are estimated using a polynomial approximation. Conduction in the airfoil skin is taken into account with a one-dimension model. Numerical results are compared with experimental and numerical results from NASA for three different icing conditions. The comparison shows that surface temperatures are very sensitive to the water droplet impingement limits. The integral method used here failed to predict correctly the heat transfer coefe cients in the transition region of the boundary layer. When experimental heat transfer coefe cients are used, the model gives satisfactory results.