A two-phase logarithmic law of the wall for isothermal bubbly turbulent boundary layer is developed. Total boundary layer liquid turbulent stress is estimated by the sum of bubble induced local stress and sheer induced stress. Boussinesq turbulent viscosity approximation is assumed to be valid for both stress components. A proportionality coefficient was introduced to account for inherently non-linear interaction between shear and bubble induced turbulence fields. The two-phase wall law was implemented in CFX4.2 computational fluid dynamics program. A better agreement with experimental data was achieved when the new wall law was employed rather than conventional single-phase law. (C) 2001 Elsevier Science Ltd. All rights reserved.