A method and an apparatus for completing a circuit switched service call in an Internet Protocol network are disclosed. For example, the method receives a session request and queries an tElephone NUmbering Mapping server for a called party, and determines if at least one Naming Authority Pointer resource record associated with the called party is received from the ENUM server. The method determines if a Session Initiation Protocol Universal Resource Identifier is returned, if the at least one NAPTR resource record associated with the called party is received, and processing the session request using the SIP URI, if the SIP URI is returned. The method determines if the processing of the session request using the SIP URI resulted in a successful call completion and processes the session request using a telephone URI, if the processing of the session request using the SIP URI resulted in an unsuccessful call completion.