The Hospital Information System (HIS) is a key digital platform facilitating communication and information sharing. Despite its potential, full utilization of HIS remains limited. This study explores factors influencing HIS adoption in Croatia, focusing on expected performance, expected effort, social influence, and system support. Data from a survey conducted at General Hospital Bjelova was analyzed through Partial Least Squares Structural Equation Modelling (PLS-SEM). Results show that expected performance and effort significantly enhance the intention to use HIS. Social influence from colleagues positively impacts intention, while administrative processes negatively affect it, fostering resistance among users. Intention to use HIS positively correlates with its intensity in daily operations but negatively affects occasional usage. These findings provide insights into optimizing HIS implementation and enhancing user engagement, offering practical recommendations for healthcare administrators and policymakers.