Enhancement of forced convection is important in many engineering applications. Surface modifications like rib-roughening are commonly used in applications such as compact heat exchangers and cooling systems in gas-turbine systems. In this paper flow fields, friction factors, and local and average heat transfer coefficients in rib-roughened ducts of the type appearing are considered. Both experimental and numerical investigations are discussed. Details of the flow pattern and the influence of rib configuration, rib angle, rib pitch, and rib height are discussed and physical interpretation of the results are provided. Some general conclusions are provided but it is also found that accurate numerical modelling of the flow and heat transfer from ribbed surfaces is difficult. Suggestions for further research are given.