A method and system for providing improved wireless number portability. This invention allows the mobile switching center (MSC) to use a separate database to store the number portability information gathered earlier through sending NPreq messages to the number portability database (NPDB) and various strategies for refreshing or updating the internal database. The invention enables the MSC to use the separate database to check whether a portable number is ported and what the associated location routing number (LRN) if it is ported, so that the MSC does not need to send NPreq messages to the NPDB many times for the same ported number. This invention may apply to any number of switching systems, including CDMA, GSM and UMTS mobile switching systems.