The present study deals with the effects of wall geometry on the fluid flow and heat transfer in a vertical channel with a wavy wall. The waviness is characterized by wave amplitude and period. The wavy wall is heated with a constant heat flux. A detailed parametric investigation of the effect of waviness is performed for different flow conditions. An enhanced version of the turbulence models is required in order to resolve the near-wall region. In particular, a single wall law for the entire wall region can be achieved by blending linear (viscous) and logarithmic (turbulent) laws-of-the-wall. This approach allows the fully turbulent law to be easily modified and extended to take into account other effects such as pressure gradients or variable properties. Second order discretization scheme for momentum equation and turbulence scalar equations was used. SIMPLE pressure-velocity coupling scheme was employed. The results show how the flow and geometry parameters, namely, the Reynolds number and the amplitude and period of waviness, affect such features as the existence of flow separation, its location and size of the recirculation zones. These features determine the temperature distribution on the wavy wall. An attempt is done to assess the effect of flow and geometry parameters quantitatively.