Separated flows are widespread in many areas of science and technology, such as space technology, aviation, gas turbines, etc., which has a significant effect on the processes of hydrodynamics and heat transfer in them. The separation of the flow and its reattachment can serve as a powerful means of enhancing heat and mass transfer processes, and its organization is quite simple and reliable in terms of technology. This paper presents the results of the experimental study on hydrodynamics and heat transfer in the separation zone in front and behind a single rectangular perforated rib located on a flat plate heated by the law of qw = const. Experimental measurements were carried out using the Pitot-Prandtl tube and Dantec Dynamics hot-wire anemometry system, which allows us to obtain new characteristics of the turbulent boundary layer, both mean and oscillatory ones. We analyzed the influence of the perforation ratio of the rib and the location of the holes in the rib on the heat transfer efficiency. It was established that the stagnant and recirculation zones in front and behind the perforated rib were shifted and became smaller or disappeared. Findings of research show that jet flows, impinging on the heat transfer surface from the perforation holes, provide more efficient heat transfer behind the perforated rib, compared to that behind the solid rib.