Background: The study examines trust among patients with Severe Mental Illness (SMI) in mental health services providers. Study's hypothesis suggests higher level of patients' trust inthe biosocial model advocated by social workers in comparison with the biomedical model advocated by psychiatrists. Method: The study includes 60 participants (N=60), living in the community, with a history of psychiatric hospitalization. All Participants were in constant contact with psychiatrist (9 psychiatrists) and social worker (11 social workers) for a minimum period of six months.Findings: Study findings indicates that, in accordance with the hypothesis, the level of trust toward social workers was significantly higher compared to psychiatrists.In the context of the biomedical model,asignificant correlation was found between duration of contact with a psychiatrist and betweenpatient’s level of trust. Moreover,frequency of therapy sessionsfound to be the only variable predicting level of trust felt towards psychiatrists.In the context of thepsychosocial model,duration of contact, frequency of therapy sessions and number of readmissions since first hospitalization, were found to predict the level of trust felt toward social workers. Conclusions: Increasing frequency of sessions between a psychiatrist and his patient will create the essential conditions that shall allow a professionals to create a higher levels of trust among patients. In the other hand, reduced number of readmissions may retain the trust level felt toward social workers.