The atmospheric entry of a meteor is quite complex, with the body losing kinetic energy both from atmospheric drag and from mass loss due to aerodynamic heating. Moreover, high pressures on the windward side of the body result in enormous compressive stresses which may exceed the yield strength of the material and cause rapid fragmentation of the meteor. While ablative mass loss is not important for extremely large objects, it must be accurately estimated to correctly predict the trajectories of objects that are several tens of meters in diameter. The current paper describes a computer model which performs calculations of shock layer conditions, accounting for the time varying temperature distribution, radiative cooling of the shocked gases, and blockage of surface heating by ablation products. Application of the model to the well-known Tunguska Event indicates that the responsible bolide was probably a carbonaceous chondrite, although a stony asteroid or a cometary body cannot be conclusively ruled out. ¿ American Geophysical Union 1996