Prefabricated mass timber-based floors are lightweight flooring alternatives gaining attention in building applications given their ease of erection, low carbon footprint and structural benefits in reducing the overall seismic mass and foundation requirements in buildings. However, in these floor archetypes, serviceability limit state requirements such as deflection and vibration performance often govern member sizing and layout design. In this paper, the vibration properties of one such flooring system – a prefabricated cross-laminated timber (CLT) - steel hybrid floor, are examined at full-scale via modal and walking tests, considering variations in material properties, geometric configurations, support conditions, walking paths and walking frequencies. The test results indicate that the composite floor is a high-frequency system with a transient response. The study also provides valuable insight into the potential vibration performance of CLT-steel composite floors for residential applications. A prediction of its vibration serviceability via the vibration dose value method indicates that it has a low probability of attracting adverse comments from users in residential applications when a continuous slab is created by connecting its fundamental units using self-tapping screws.