Trust is a social code and glue between persons and organizations in any business domain including health. pHealth is a complex concept that is built around health service providers, individuals and artefacts such as sensors, mobile devices, networks, computers, and software applications. It has many stakeholders such as organizations, persons, patients, customers, and tele-operators. pHealth services are increasingly offered in insecure information space, and used over organizational, geographical and jurisdictional borders. This all means that trust is an essential requirement for successful pHealth services. To make pHealth a successful business, organizations offering pHealth services should establish inter-organizational trust and trusted relationship between their customers. Before starting to use services, the pHealth user should have a possibility to define how much it trusts on the service provider and on the surrounding information infrastructure. The authors' analysis show that trust models used in today's health care and e-commerce are insufficient for networked pHealth. Calculated trust as proposed by the authors is stronger than the predefined dispositional trust model currently used in health care, other's recommendations used in e-commerce and risk assessment. Until now, caused by the lack of business incentive, lack of regulatory and political pressure, pHealth providers have not demonstrated meaningful interest in moving from the current unsatisfactory situation to trust calculation by making information necessary for this methodology available. To make pHealth successful, a combination of legal, political, organizational, technological and educational efforts is needed to initiate the paradigm change and start the era of trust-based pHealth services.