Abstract: The present invention discloses a method for executing roaming restrictions in GPRS and UMTS networks. A preferred embodiment of the present invention purposes that the SGSNs of the network stores the IMSI numbers or IMSI series having roaming restrictions in parts or whole of the respective areas covered by the SGSNs. The SGSNs may then easily check if an MS is allowed to roam into an area when receiving the MS data in an initiated roaming procedure, and then be able to terminate the procedure in time before the old SGSN is made unable to keep handling the MS. Other embodiments of the present invention propose to provide the roaming restrictions for the respective MSs from the subscription data in the HLRs early in the roaming procedure so that it may be terminated in time. By means of the present invention, unnecessary disconnections of MSs from the network in connection with roaming are avoided This is expected to be a growing problem in GPRS and UMTS networks implemented according to the current standard.