This chapter offers a general overview of the often spectacular rise of the share of cohabitation in the process of union formation in 24 Latin American and Caribbean countries during the last 30 years of the twentieth and the first decade of the twenty-first century. First, we offer a brief ethnographic and historical sketch to illustrate the special position of many Latin American regions and sub-populations with respect to forms of partnership formation other than classic marriage. Second, we present the national trends in the rising share of cohabitation in union formation for men and women for the age groups 25–29 and 30–34. Third, we inspect the education and social class differentials by presenting the cross-sectional gradients over time. Fourth, we reflect on the framework of the “second demographic transition” and hence on the de-stigmatization of a number of other behaviors that were equally subject to strong normative restrictions in the past (e.g. divorce, abortion, homosexuality, suicide and euthanasia). Last, we deal with the household and family contexts of married persons and cohabitors respectively.