Background and aims: Today, the impact of the spiritual attitudes of patients and physicians on the patients' treatment is a subject that has attracted the interest of many experts and scholars. Recent researches have shown that the spiritual attitude can be effective on the treatment process. The main aim of this survey was to examine the attitudes of patients in Tehran about the effects of spirituality on their treatment process.Materials and Methods: Using the convenience sampling method, one thousand patients who referred to hospitals in Tehran were chosen to participate in this study. A valid questionnaire the validity of which has been confirmed by the experts was used in this study to assess patients' spiritual attitudes. Different dimensions such as: being spiritual and/or religious, religiosity degree, quality of life, stress scale, and preferring treatment by physicians who believed in the impact of spirituality on the treatment were all assessed by this questionnaire.Results: Findings showed that there was a significant and direct relationship (r=11%, p=0.004) between patients' being religious or spirituality and their quality of life and treatment. There was a significant relationship between quality of life and patients' spirituality rating and also between belief in the spirituality impact on treatment and patients' being religious and spiritual (p<0.001, r=289%). There was a slight difference between two sexes. There was no significant relationship between men's spirituality and religiosity and stress, however in women, there was an inverse relation between these two variables.Conclusion: There is a significant and direct relationship between patients' being religious and spiritual and their quality of life and belief in effectiveness of spirituality in treatment.