The deal, worth over $1bn (£703m), is the largest ever for Nokia's network equipment division.
Cingular announced in October that it would move from its existing Time Division Multiple Access (TDMA) network to GSM technology in order to offer customers fast wireless data connections.
At the time, the company said that it would spend $3bn (£2.1bn) on upgrading its networks and was working on deals with Nokia, Ericsson and Siemens to provide the network, services and handsets.
Ericsson also announced that it had signed a contract with Cingular Wireless, though it would not release terms of the deal.
"We are not in a position to give any dollar figure, but of the three players named as part of the build-out, we are significantly the largest," said Ericsson spokesman James Borup. "We got about 60% of the core network and just less than half of the radio part," he added.
Nokia is expected to supply the equipment for Cingular's GSM network by early 2002.
Cingular, like other wireless telecommunication companies, plans to build out its next generation networks in phases: from GMS to GPRS to 3G. The company plans to have 50% of its current network served by GSM by the end of 2002, with its GPRS network available across the US by 2004.
Rival company AT&T Wireless Group announced a move to GSM and GPRS last year, and also has contracts with Nokia and Ericsson for similar infrastructure equipment.