The aim of this study was to describe the role of spirituality and religiousness (SR) among detainees. Thirty detainees from a French short-stay prison were assessed with the World Health Organization Quality of Life–Spirituality Religion and Personal Beliefs questionnaire (WHOQOL-SRPB) and with open questions about SR. Forty percent of detainees described SR as an important way of coping with incarceration and stressful events, as a means of finding inner peace, showing altruism, and gaining the respect of others. SR involvement was associated with reports of decreased suicide risk and of the prevention of future offences. SR appears to be an important coping mechanism and may help the transition to the community following incarceration. This study endorses the view that SR should be considered when treating this population.