This paper presents a new angular discretization scheme, FTn of the finite volume method (FVM) in three-dimensional radiative heat transfer. The FTn FVM is applied to absorbing, emitting and anisotropically scattering media with variable optical thickness in a rectangular enclosure. Results show that the FTn FVM performs better than the discrete ordinate method (DOM) and the FVM with N-theta x N-phi uniform angular discretization except near the optically thick diffusion limit. The FTn FVM closely reproduces the reference solutions by the Monte Carlo method for different scattering phase functions and optical thicknesses. It also turns out that anisotropic scattering has significant influence on radiative heat transfer with a symmetric boundary condition in a moderate optical thickness range as well as with a nonsymmetric boundary condition. (C) 2000 Elsevier Science Ltd. All rights reserved.