The use of rib roughness in numerous forms, shapes and sizes is the utmost common and effective way to increase the thermohydraulic performance of a rectangular duct. Investigators reported various rib roughness shapes in the literature for studying fluid flow and heat transfer in rectangular duct. A number of experimental and CFD studies carried out on rib roughened rectangular duct for their performance analysis were reported in the literature. This comprehensive review of literature reveals that a lot of work has been described on design of rectangular duct by experimental approach. This review also reveals that rare studies have been done on CFD analysis of rectangular duct.