[en] Blood irradiation is known as the best method to prevent the risk of transfusion-associated graft- versus-host disease (TA-GvHD). Gamma-irradiation was commonly used for blood product irradiation where Caesium-137 (Cs-137) is utilised as a main radioactive source with activity ranging 40 - 120 TBq. Cs-137 is assigned to Category 1, corresponding to security Level A based on the IAEA Code of Conduct on the Safety and Security of Radioactive Sources and IAEA Nuclear Security Series. The purpose of this study is to evaluate the nuclear security culture in organization and to determine how extensive nuclear security as part of the organisation’s culture. Two locations were chosen as a research location which is National Blood Centre and Ampang Hospital. The system was assessed through surveys and interviews where questionnaires was distributed to all respondent that inclusive medical officers, science officers, medical laboratory technicians and hospital attendants. The interviews session was conducted by one interviewer and few observers for verbal and non-verbal data collection. The study found that security system and policy are already in place but the security culture is not fully practiced by all staff. Management foresees the need of structured training programme to improve staff understanding on security culture. Even though majority of the staff are aware of security culture, they still didn’t embraced the security culture due to lack of awareness on the potential threat. Improvements can be made by developing a comprehensive nuclear security training programme, encouraging effective communication between top management and staff members and ensure staff members adhere to procedures in order to support and enhance nuclear security. Apart of conducting another round of self-assessment on nuclear security culture for government, private and university hospital, there also will be initiative to develop a close cooperation with IAEA and to be listed in Integrated Nuclear Security Support Plan (INSSP) 2018-2021 as part of the future plan. (author)