In this paper, a model of reliability assessment of services in Home Health Care Delivery is presented. Reliability is an important quality dimension for services and is included in non-functional requirements of a system. A stochastic Markov model for reliability assessment is applied to patient communication services, in the field of home health care delivery. The methodology includes the specification of scenarios, the definition of failures in scenarios as well as the application of the analytical model. The results of the methodology reveal the critical states of the Home Health Care System and recommendations for improvement of the services are proposed. The model gives valuable results in predicting service reliability and, independently of the error types, it can be applied to all fields of Regional Health Network (RHN).