This paper deals with various issues on testing heat exchangers at cryogenic temperatures, the test setup and experimental studies on perforated plate heat exchangers. A number of fluid flow circuits are used in practice for testing a heat exchanger at cryogenic temperatures. These circuits are reviewed and a simplified fluid circuit is proposed with justifications. Effects of the fluid inlet/outlet tubes on the performance evaluation of the heat exchanger were investigated numerically. It is found that convection heat transfer between fluid and the tube as well as conduction heat transfer through the tube walls can cause significant errors in the evaluation. These errors are considered while designing the inlet/outlet tubes for the test setup. Details of the test setup including mounting of temperature sensors, instrumentation and data acquisition are discussed. Some selected data from our experimental studies on perforated plate heat exchangers are presented. Transient study on the heat exchanger by using the setup is also demonstrated. For pressure drop studies, a separate test setup is used.