Two basic problems in the development of a thermoelectric refrigerator are the construction of a cooling unit, consisting of the thermoelectric junctions, and the optimization of the complete refrigerator design to make best use of the thermoelectric material. It is essential for the unit to achieve good thermal contact with the cooling chamber and to have good electrical contact across the p and n semiconductor bars forming each junction. A simple but accurate method for measuring the junction resistance is shown, and the relative merits of various methods of forming the cooling unit are discussed. The heat balance equations for a refrigerator are given which include the cooling fin system, and the method of optimization of the design is noted.