The role of Nurses' aides (NAs) in the clinical practice has been widely debated to date. To describe the activities/tasks performed by NAs and the dedicated time; to identify the activities/tasks shifted from nurses to NAs and to investigate the motivations. A multi-center mixed-methods study was conducted. Fifty-six NAs working in 17 hospitals in the North-Italy were observed during daily practice and then interviewed about the motivations associated with task shifting. NAs mainly performed direct care tasks (67.7% of the observed time), such as helping with personal hygiene, feeding and mobilization. Larger hospitals (p = 0.034), surgical units (p = 0.001), a skill mix> 40% (p = 0.044) and a reduced nurse to patient ratio (p = 0.041), were significantly associated with a higher amount of indirect care activities/tasks performed by NAs. The tasks shifted most frequently from nurses to NAs were: mobilization (22; 39.3%) and personal hygiene (21; 37.5%) of unstable patients, feeding patients with dysphagia (19; 34%), intra-venous set replacement (16; 28.6%) and pressure ulcers' dressing (11; 19.6%). NAs reported that they chose to act autonomously because of their experience and the trust-based relationship with nurses, in order to promptly respond to patients needs and to reduce nurse workload. It is necessary to further assess the development of the NAs role in the hospital setting to understand their inclusion in the nursing care.