The NASA Center for Climate Simulation (NCCS) plays a lead role in meeting the computational and data management requirements of climate modeling and data assimilation. Scientific data services are becoming an important part of the NCCS mission. The NCCS Data Management System (DMS) is a key element of NCCS's technological response to this expanding role. In DMS, we are using the Integrated Rule-Oriented Data System (iRODS) to combine disparate data collections into a federated platform upon which various data services can be implemented. Work to date has demonstrated the effectiveness of iRODS in managing a large-scale collection of observational data, managing model output data in a cloud computing context, and managing NCCS-hosted data products that are published through community-defined services such as the Earth System Grid (ESG). Plans call for staged operational adoption of iRODS in the NCCS.