Patient mobility is considered one of the main concerns for policy-makers as it impacts financial sustainability of regional health systems due to the high percentage of patients accessing care services in other regions. For a better understanding of this phenomenon, it is necessary to define a behavioral model able to represent the patient-system interaction. In this paper we adopted the Agent-Based Modelling (ABM) approach with the aim of simulating patient flow across regions and determining which are the main factors influencing it. This may provide a new insight for policy makers to capture which are the main factors influencing mobility and actions that may contribute to contain this phenomenon.