From a paratransit perspective, the article characterizes the relationship between urban passenger transport and expansion in the metropolitan area of Cochabamba. It argues that the urban growth of this metropolis is, among several factors, the result of the conditions of the passenger transport service, cha racterized by its informality, autonomy, freedom, and flexibility. It postulates that the transport service is a fundamental device for the consolidation of urbanization, through three types of relationship with new settlements: 1) consubstantiality between neighborhood organization and transport service organization; 2) neighborhood organization requesting transport services; and 3) transport operator offering specific services for the demand. In addition, three forms of agency on the routes are added: creation, extension and subdivision. In closing, we reflect on the importance of this phenomenon as a central factor in understanding the urbanization conditions of Bolivian cities.