OBJECTIVES: For some people, diagnosis with a serious illness or other adverse life events can precipitate a period of religious struggle. While evidence of the harmful effects of religious struggle is accumulating, less is known about its prevalence or correlates. The aim of this study was to examine the prevalence and correlates of religious struggle in three groups of medical patients. METHODS: Study participants included diabetic outpatients (N= 71), congestive heart failure outpatients (N = 70), and oncology inpatients (N = 97). Participants completed questionnaires which included several measures of religion, including religious struggle, emotional distress or well-being, and demographic characteristics. RESULTS: Half of the total sample (52%) reported no religious struggle, while 15% reported moderate or high levels. In a multi-variate analysis, younger patients (p < 0.001) and CHF patients (p < 0.05) had higher levels of religious struggle. Those with higher levels of positive religious coping also reported higher levels of religious struggle (p < 0.01), while those who attended worship most frequently had lower levels of religious struggle (p < 0.05). Religious struggle was associated with higher levels of depressive symptoms and emotional distress in all three patient groups. CONCLUSIONS: While further research is needed to help clarify the sources, additional correlates, and course of religious struggle, the findings in this study confirm the association between religious struggle and emotional distress in these three groups of medical patients. Clinicians should be attentive to signs of religious struggle. Where patient’s responses indicate possible religious struggle, clinicians should consider referral to a trained, professional chaplain or pastoral counselor.