Trust is a key element in the physician-patient relationship. Imam Jafar Sadiq (A.S.) stated that the proficient and trusted physician is in equal level of a just jurisprudent. Ancient ethical texts put much emphasis on physicians to be trusted. Nowadays, trust is a component of social health; we believe that in the physician-patient relationship, trust has a significant impact on the practice, and increases the effectiveness of treatment and the satisfaction of patient and physician? also patient autonomy is preserved, health is positively reinforced, and patients will be more serious and less negligent with expenses, treatment, and follow up. This paper is a review/analytical article, and aims at classifying trust and examining its role in communication between physician and patient. If limited to practice, trust in the physician - patient relationship is divided into two types:

1- Unconditional trust, which means full confidence with no autonomy

2- Conditional trust, which entails maintaining autonomy.

 In the first type, where patient's autonomy is foregone, both patient and physician can be blamed. The patient is to blame due to an absence of self confidence and lack of participation in decision making and treatment, and the physician might in his place have the tendency to patronize. In this article we emphasize the importance of trust and warn against paternalism and conclude that if doctors truly comprehend the meaning of trust, they will try to avoid paternalism.