A location updating method and apparatus for a mobile terminal in a radio network is provided for preventing a location updating request of a mobile terminal from being rejected by a network with an invalid cause of a rejection. The location updating method for a mobile terminal includes receiving a location updating reject message from a first network, the location updating reject message including a cause of a rejection indicating that the mobile terminal is not registered with the first network, checking a first network information of the first network, determining whether the first network information differs from a second network information of a second network, maintaining, when the first and second network information are different from each other, an operational state of the mobile terminal as a valid state, and requesting, when the home network is discovered, the home network for a location updating.