Many geothermal phenomena have been recognized in Japan: thermal Springs and spas, for instance, have been part of the traditional Japanese way of life since Antiquity. These occurrences are related to the important past and present volcanism in the circum-Pacific orogenic belt of which Japan is a part. The geothermal fields occur principally in the upper Tertiary green tuff volcanic formations and in Quaternary volcanic areas. Two distinct types of geothermal systems can be distinguished: the hot-water systems (Otake, Hatchobaru, Onuma) and the vapor-dominated systems (Matsukawa, Onikobe). Integrated geothermal exploration is carried out by several methods. Detailed geological mapping is used to locate favourable geothermal areas such as fault systems, grabens, calderas, depressions filled by Quaternary volcanic formations, hydrothermal alteration patterns, etc. Geochemical sampling of thermal waters and steam provides useful information on the potential underground temperature and can be utilized to predict the depth and capacity of the geothermal field, and to establish drilling sites. Geophysical methods can be applied to detect those geothermal reservoirs not evident at the surface. Their depth and permeability can also be estimated by these methods. Remote sensing measurements and, in particular, infrared teledetection are increasingly applied. Drilling for geothermal energy is carried out with methods similar to those used in oil exploration but technical problems caused by high temperature, pressure and corrosion have to be taken into account. At present five geothermal power plants are in operation with a total installed capacity of 90 Megawatts. In relation to the total power requirement of the country this capacity is still rather small, but projects now under way will give a geothermal power production of 350 MW for 1980 and 50,000 MW by the end of the century. The cost of geothermal power is competitive and in many cases significantly cheaper than that produced by conventional thermal or nuclear plants. The Japanese geothermal power industry is very active within the country and abroad, and Japan will certainly play an important part in the study and development of geothermal energy.