Aspects of the invention provide a method, system and computer program product for managing multiple user identities for a user of an electronic commerce (e-commerce) site. The method comprises defining the e-commerce site as one or more security domains; and in response to a user's request to invoke an operation of the e-commerce site: determining a one of the one or more security domains to which the operation relates; performing one of a) creating a session and b) reusing a session for the user automatically in accordance with the determined security domain, said session associated with a user identity and a role indicating privileges for invoking operations of the e-commerce site in at least the determined security domain; and persisting said session for reuse. The user's request may be received in association with one or more sessions persisted for the user and a one of the sessions selected in accordance with the determined security domain. In response, either a session may be created or reused. Persisting may comprise providing one or more cookies defining the session to the user for associating with a subsequent request.