Abstract The rapid development of electronic devices has made it necessary to develop novel and innovative thermal management solutions. This paper experimentally investigated the heat transfer and flow characteristics of three new finned copper foam heat sinks subjected to the impingement cooling by rectangular slot jet and axial fan. The effects of heat sink height (H, 15, 30, 45, 60 mm), the pore density of the inserted copper foam (PPI, pore per inch including 10, 20, and 30) and the gas flow Reynolds number (Re, varying from 2053 to 12737), were systematically investigated. Two kinds of conventional finned heat sinks, with 8 and 22 fins but without copper foam, were also tested for comparison. Experimental results reveal that inserting copper foam positively improves the thermal performance of finned heat sinks subjected to jet impingement. In addition, the thermal performance of finned copper foams with 20 PPI and 30 PPI even exceeds that of a conventional finned heat sink with 22 fins at a low height such as 15 mm, showing a great potential to replace traditional finned heat sinks. However, inserting metal foams leads to a much larger pressure drop than those of conventional finned heat sinks. From this work, finned copper foams are characterized by a better heat transfer performance than a conventional heat sink with the same number of fins. Even with increased flow resistance, finned copper foam heat sinks still have application prospects in some limited and narrow spaces where pump power consumption is not the dominant consideration.