The European Commission's Joint Research Centre has published its annual report for 1993 concerning the operation of the High-Flux Reactor (HFR) at the JRC Institute for Advanced Materials (Petten). The report covers activities carried out in 1993 in the following areas: - HFR operation, maintenance, development and support; - HFR utilization; - General activities; - Quality assurance. In 1993 the HFR achieved a total of 279 operation days, corresponding to an overall availability of 76%. The reactor was used for research programmes in support of nuclear fission reactors and thermonuclear fusion, for fundamental research with neutrons, for radioisotope production, for Boron Neutron Capture Therapy (BNCT), and for various smaller activities. General activities in support of running irradiation programmes progressed in the normal way, and significant efforts were made with regard to quality assurance for the safe and efficient operation of the reactor.