We present the recent research findings of our group that allowed us to investigate the potential links between religiosity/spirituality and different indicators of mental health. Thus this paper represents a synoptic overview of the most important results which were gathered by applying the Multidimensional Inventory for Religious/Spiritual Well-Being (MI-RSWB) to different personality dimensions and to different facets of subjective well-being and mental health in several studies. The MI-RSWB was applied on different clinical samples (e.g. depressive or addiction inpatients) and non-clinical samples together with different well established measures for personality (e.g. NEO-FFI), subjective well-being (e.g. Sense of Coherence-scale) or mental illness (e.g. Beck Depression Inventory). Data were evaluated by conducting correlation statistics as well as GLM multivariate for group comparisons. Taken together, this body of research suggests that there is substantial evidence for religiosity and spirituality being positively related to a variety of indicators of mental health, including subjective well-being and positively correlated with the personality dimensions of extraversion and negatively correlated with neuroticism. Overall we found out that religiosity and spirituality can play an important role in the process of recovering from mental illness as well as providing a protective function against addictive or suicidal behaviours. However, further research is needed to examine the mechanisms through which religiosity and spirituality has an impact on health related conditions.