The company, which has 320 stores in the UK, trialled RFID in October and November of last year to test the technology and gauge levels of customer acceptability.
The test highlighted hardware and software modifications that Marks & Spencer would need to make before implementing the technology.
A portal, which was installed at the distribution centre and the loading bay of the store to allow rails of hanging garments and trolleys to be pushed through and read at speed, was found to provide a less accurate reading than a mobile scanner that was trialled. The portal was also less versatile.
The mobile scanner could potentially represent better value, but a number of design modifications would be required, Marks & Spencer said.
The PC integrated into the scanner would need to be "ruggedised" - contained within a more robust casing with a smaller screen - and the role of the scanner would be changed to that of a transmitter rather than a processor of information, Marks & Spencer said.
James Stafford, head of RFID at the retailer, said, "We are pleased with the trial's outcome - it proved that this technology can work within a retail store.
"We need to establish a robust business case for the technology, so we will be trialling it in more stores and for a longer period of time to get meaningful figures."