Some results of a detailed study of neutron diffusion in water containing 1/v and non-1/v absorbers are reported. We have solved the Boltzmann transport equation in the diffusion approximation using the multigroup method and the recent neutron scattering kernel proposed by the authors. The calculated values of diffusion length, L(T), in pure water in the temperature range from 0.5 to 60°C are found to be in good agreement with most of the experimental results. (Results based on the Nelkin kernel are consistently higher.) The variation of L(T) is nonlinear up to 10°C, but in the temperature range from it can be expressed as L(T) = L (10°C) + 0.00446 (T − 10). The computed values of the diffusion length in water poisoned with various concentrations of boron are consistent with the experimental results of Martinho and Costa Paiva. For non-1/v absorbers—cadmium and gadolinium solutions—calculations on space-dependent neutron spectra are reported. The calculated values of for various concentrations of cadmium and gadolinium are in good agreement with the experimental data of Goddard and Johnson. For high concentrations of cadmium, notable differences are observed between the present calculations and those based on the Nelkin kernel.