Substance addiction is damaging to the health of persons, families, and society. Often the person with addiction has decreased spirituality and religiosity and suffers from anxiety, depression, or both, increasing the risk for continued substance use and its concomitant negative consequences. The study purpose was to describe spirituality and religiosity, among persons enrolled in methadone maintenance therapy and to examine associations between spirituality, religiosity, anxiety, depression, and drug-use consequences. Using a descriptive and cross-sectional correlational design, 108 participants completed questionnaires assessing the study variables. Spiritual well-being was similar to other addiction samples and lower than healthy person samples. Most participants described themselves as spiritual or religious though religious participation was lower than in their past. The analysis indicated that spirituality, religiosity, depression, anxiety, and negative drug-use consequences are interrelated in the person with addiction. Higher anxiety was predictive of negative drug-use consequences.