Well-being and mental health are not only direct functions of amount of stress, but also depend on how people appraise and face critical situations. Spiritual well-being seems to be a central component of psychological health in physically healthy individuals and it offers some protection against end-of-life despair in those with chronic diseases. In this study, 250 out and in-patients with a cancer diagnosis were interviewed with standardised instruments to measure two aspects of spirituality, existential and religious well-being, coping strategies, psychological state, and quality of life (QoL). Using multivariate logistic regression models we found that coping strategies characterized by acceptance and positive reinterpretation of the stressor, and the absence of anxiety disorder, independently increased the likelihood of the existential well-being (Odds Ratio, OR, 7.7, and OR, 4.5, respectively), whereas religious well-being was not significantly associated with these variables. Our findings show that existential and religious well-being may be very different. A spirituality-based intervention could be differently utilized by patients with different beliefs, cognitive and behaviour characteristics. Measure of coping strategies and psychological state should be part of routine management of cancer patients.