MSISDN（Mobile Subscriber International ISDN number）移动台国际用户识别码，即移动用户的ISDN号码，是在公共交换电话网交换网络编号计划中，唯一能识别移动用户的号码。

MSISDN由国家码和国内有效移动用户电话号码两部分组成，后者又包括国内目的码和用户号码两部分。 中国的国家码为86，国内有效电话号码结构为：N1N2N3＋H0H1H2H3＋ABCD，N1N2N3为数字蜂窝移动业务接入号，需遵循通信主管部门的分配原则；H0H1H2H3为HLR识别码、ABCD为移动用户的编号，需遵循各电信业营者的编号原则。

MSISDN (pronounced as /'em es ai es di en/ or misden) is a number uniquely identifying a subscription in a GSM or a UMTS mobile network. Simply put, it is the telephone number to the SIM card in a mobile/cellular phone. This abbreviation has a several interpretations, the most common one being "Mobile Station International Subscriber Directory Number".