Human noroviruses (NoV) are the main pathogenic agents worldwide responsible for viral sporadic and epidemic gastroenteritis worldwide. A gastroenteritis outbreak broke out in patients hospitalized in several wards located in two different floors of a hospital in Liege, Belgium. The objective was to determine whether a same NoV strain would be involved in the two different floors, and to explore how this outbreak would have spread from a floor to the other. Stool samples from patients and healthcare workers were collected, as well as data from medical files. NoV detection, quantification and characterization were performed using molecular biology methods. A same NoV strain, from genotype GII.4, was detected in two patients hospitalized on the two different floors. This finding allowed to conclude that a same outbreak spread in the two floors, probably due to movements of common healthcare workers. A rapid NoV detection during outbreak is important in the aim to rapidly implement hygiene measures to limit the size of the outbreak.