This study considers numerical modelling based on the Computational Fluid Dynamics technique for a hospital ward with an upper-room ultraviolet germicidal irradiation fixture. A two-bed hospital ward equipped with a ceiling-level low-velocity ventilation diffuser was considered. The airflow field was considered steady state and ultraviolet distribution was treated as a scalar flux. Different particle sizes were simulated representing the pathogenic contaminants released from patients’ breathing zones. The results confirm the effectiveness of ultraviolet germicidal irradiation. However, an optimization study should be performed to enhance the disinfection efficiency of the system. Ultraviolet germicidal irradiation is an effective technique for airborne bacteria inactivation which potentially can be used to prevent the spread of certain infectious diseases.