As the essence of health in humans, spiritual health is a fundamental concept for discussing chronic diseasessuch as cancer and a major approach for improving quality of life in patients is through creating meaningfulnessand purpose. The present descriptive analytical study was conducted to assess the relationship between spiritualhealth and quality of life in 210 patients with cancer admitted to the Cancer Institute of Iran, selected throughconvenience sampling in 2014. Data were collected using Spiritual Health Questionnaire and the EuropeanOrganization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC-QLQ). Patients’performance was assessed through the Karnofsky Performance Status Indicator and their cognitive statusthrough the Mini-Mental State Examination (MMSE). Data were analyzed in SPSS-16 using descriptive statisticsand stepwise linear regression. The results obtained reported the mean and standard deviation of the patients’spiritual health scoreas 78.4±16.1and the mean and standard deviation of their quality of life score as 58.1±18.7.The stepwise linear regression analysis confirmed a positive and significant relationship between spiritual healthand quality of life in patients with cancer (β=0.688 and r=0.00). The results of the study show that spiritualhealth should be more emphasized and reinforced as a factor involved in improving quality of life in patientswith cancer. Designing care therapies and spiritual interventions is a priority in the treatment of these patients.