Bi0.99Sb0.01 thin films were vacuum deposited on glass substrates at room temperature. X-ray structural studies were performed. The thickness dependence of both the dc electrical resistivity and the Hall coefficient were carried out at room temperature over a thickness range from 30 nm to 200 nm. The type of conduction, the concentration and the mobility of charge carriers were revealed. Analysis incorporating the electrical resistivity and the Hall effect data led to the determination of the specular and non-specular size-effect parameters. Parameters such as the bulk resistivity (ro), bulk mean free path (lo), grain-boundary transmission coefficient (p-), external surface parameters (U), surface scattering factor (p) and grain-boundary parameter (V) were all evaluated without using any adjusting parameters. Beside the background contribution to the film resistivity, an estimation of the contribution of the surface and grain boundary to the film resistivity were also carried out.