A model based on social exchange theory was developed to examine antecedents and consequences of contingent workers' commitment to their agencies and their client companies. In terms of antecedents, it was hypothesized that organization (client) procedural justice would be positively related to perceived organizational,support (client), which in turn would be positively related to commitment to the client organization. Similarly, we proposed that agency procedural justice would be positively related to perceived agency support, which in turn would be positively related to commitment to the agency. Regarding the consequences, client organization commitment was hypothesized to be positively related to managerial ratings of contingents' altruistic organizational citizenship behaviors (OCBs) and managers' perceptions of contingents' commitment to the client company. Finally, whether agency commitment,spills over' to influence managers' perceptions of contingents' commitment to the client organization was examined. Using a sample of 98 contingent workers with matched data from their managers at the client organization and structural equation modeling analyses, we found support for all of the hypothesized relationships. Copyright (C) 2003 John Wiley Sons, Ltd.