The Fifth International Conference on Geochronology, Cosmochronology, and Isotope Geology was held from June 27–July 2, 1982 in Nikko, Japan. These conferences are held every 4 years to review progress in geochronology and isotope geochemistry and to discuss results of the application of isotopic techniques to problems in the earth and space sciences. The first two, held in Canada in 1966 and Switzerland in 1970, were concerned with geochronology only. In 1974 the meeting in France expanded to include cosmochronology and stable isotopes. The subsequent 1978 meeting in the United States, and this year's meeting in Japan, followed that format. At the Nikko meeting the distribution of papers among the three general themes were: geochronology, 21%; cosmochronology, 23%; isotope geology, 56%, indicating a distinct trend toward the use of isotopes as tracers to solve geological and geochemical problems in both the earth and space sciences. The increasing tendency to consider coupled isotope-chemical systematics in such studies indicates that the next meeting, to be held in Cambridge, England in the summer of 1986, will probably formally integrate trace-element geochemistry.