Abstract: The portable cellular telephone credit card calling system works in conjunction with a cellular telephone, a local cellular network and an IXC in a telecommunications network. The portable cellular telephone has a handset and a transceiver unit and a credit card and electronic control interface electronically interposed between the handset and the transceiver unit. The interface unit has a credit card reader and an electronic system which initially validates the credit card. The cellular telephone also includes electronic circuitry which establishes a first telephone communications link with the network and transmits, via the transceiver unit for the phone, to the network, credit card data, a cellular telephone ID data and the telephone number input into the handset by the user. Upon receipt of at least the credit card data, a network transceiver verifies the validity of the user's credit card.