The International Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources (BSS) establish requirements on the legal persons responsible for designing, running and decommissioning practices involving ionizing radiation. This report is intended to be of assistance to both regulators and users of radiation sources in nuclear medicine in applying the BSS to this practice. Regulators will find it useful for reviewing applications for authorization and for the inspection of the practice. Users of radiation in nuclear medicine may follow the guidance provided in order to comply with BSS requirements or equivalent national requirements. Experts recruited on IAEA missions to advise on the implementation of the BSS for the practice of nuclear medicine are expected to use the guidance given in this report rather than their own national regulations and guidance.