GC [gas chromatographic] methods of analysis of 3H- and 14C-labeled compounds that were published in the period from 1955 to mid-1976, and important applications, are reviewed. In addition to its obvious use for identification purposes, RGC [radio-gas chromatography] is mostly used for the determination of the distribution of radioactivity among the components of mixture udner analysis and for the determination of their contents and specific activities. It can be combined with chemical reactions (reaction gas chromatography). Applications that require derivatization have some limitations connected with the derivatization reaction and the stability of the derivatives. The separation of isotopic molecules by GC is also possible. For the measurement of radioactivity, a discontinuous method involving the collection of fractions and subsequent counting is often used, while for continuous monitoring of effluent activity flow-through radiation detectors (Geiger-Mueller and proportional counters, ionization chambers and scintillation methods) are used, mainly after conversion of the effluent. The possibilities of various recording techniques with respect to quantitative evaluation are surveyed and applications of RGC in the production of labeled compounds, hot-atom chemistry, organic chemistry, chemical processing, biochemistry and clinical chemistry are discussed. [Studies on rats and rabbits are mentioned.].