Abstract: Run-as credentials delegation using identity assertion is presented. A server receives a request from a client that includes the client's user identifier and password. The server authenticates the client and stores the client's user identifier without the corresponding password in a client credential storage area. The server determines if a run-as command is specified to communicate with a downstream server. If a run-as command is specified, the server retrieves a corresponding run-as identity which identifies whether a client credential type, a server credential type, or a specific identifier credential type should be used in the run-as command. The server retrieves an identified credential corresponding to the identified credential type, and sends the identified credential in an identity assertion token to a downstream server.