The subject of the present paper is the separation of hydrogen isotopes by gas chromatography using the elution technique. The suitability of various molecular sieves for this separation is first assessed on the basis of defined chromatographic separation values. The application of molecular sieve 5A as an adsorbing agent and helium as carrier gas proves beneficial. The influence of facility and operating parameters on the quality of the separation is shown in a parametric study. The investigations indicate that the separation of hydrogen isotopes on molecular sieve 5A by gas chromatography can be used both for analytical and preparative purposes.