The firm, which runs nearly 300 stores across the UK, also enjoyed a doubling of online revenues in the nine weeks to 2 January.
The sales leap will provide some cheer to M&Co, which revealed last summer that operating profits had fallen from 9.8 million to 8.6m in the year ending February 2009.
Pegging its success to the 4.3 per cent rise in UK festive sales recently revealed by the British Retail Consortium, M&Co said it was trading well ahead of the sector.
Iain McGeoch, chairman of parent business Mackays Stores, said: "This has been an exceptional Christmas for M&Co, with growing sales and profitability in the face of difficult market conditions.
"The new, younger and more trend-led feel to our ladieswear range is proving to be a huge hit with our current customers as well as enticing new M&Co shoppers through our doors."