Labelling of leucocytes with indium oxinate is currently used abroad. Labelled leucocytes are used mainly for the detection of inflammatory processes. The aim of the work was to test the binding capacity of the radiopharmaceutical preparation indium111 oxinate prepared in the Nuclear Research Institute of the Czechoslovak Academy of Science in Rez, its effect on the survival of leucocytes and its sterility. The authors' aim was also to use during separation of leucocytes Czechoslovak preparations to use this technique on a large scale in Czechoslovakia. The assembled results indicate a good quality of the used pharmaceutical preparation; the assessed values of the percentage of activity linked to leucocytes (72.85 +/- 14.95 closely after preparation and 93.74 +/- 5.91 24 hours after preparation) are consistent with data in the literature. The sterility of the solution and its influence on leucocyte vitality are also satisfactory. All work was done within the framework of preclinical tests of the mentioned preparation, as it was not yet approved for clinical use. In view of the assessed properties there are prerequisite conditions for its early use in clinical practice.