Xavante society, well-known for its dual structural aspects, provides the best documented example of a formal age-group system in South America. Although the basic features of the Xavante secular age-group system were previously described, a second age-group system in the spiritual domain is presented here for the first time. In this paper, I describe the Xavante spiritual life cycle, including a structural dynamic whereby age sets pass through age grades in alternate fashion, allocating them between two moieties. That basic morphology is shared with the secular age-group system and attests to a Xavante logic of hierarchy and symmetry as mutually constructed and non-contradictory. Interactions between the spiritual and secular age-group systems manifest in the daily experience of spiritual participants in ways that suggest plurality and contingency are essential features of Xavante social organization.