A method and system for automatically defining and provisioning organizational data in a unified messaging (UM) platform are disclosed. An adapter in a unified messaging platform connects to at least one client human resources database. Human resources information that is organized in an organizational hierarchy is retrieved from the human resources database, and hierarchical organizational data is automatically generated in the UM platform based on the organizational hierarchy of the human resources information retrieved from the human resources database. UM mailboxes are provisioned to messaging centers in the UM platform based on the hierarchical organizational data.