Using a photolithographic fabrication process microminiature Joule–Thomson refrigerators have been fabricated substantially smaller in size than hitherto and with refrigeration capacities of the order of 25 mW. The devices are 0.5×2×15 mm in size, they operate on nitrogen gas and cool to 88 K in 45 s. The fabrication process allows mass production of the devices at low cost. It was found that the theoretical models used for the design of the refrigerators are adequate at this level of miniaturization.