Half-year group sales to 30 September rose 11% to £3.929bn on pre-tax profit up 32.2% at £405.1m.
During the period, total food sales grew at twice the rate of inflation and its share of the UK food market increased from 3.8% to 4%, it said.
It also opened 29 new Simply Food stores in the first half of the year and expects to open around 20 in the second half. Trials of Simply Food in BP forecourts will also be rolled out to more locations next year, with the opportunity for 200 sites.
Stuart Rose, chief executive of Marks and Spencer, said: “While competition remains intense, we are focusing on driving profitable revenues and market share. We continue to improve and develop our customer offer in core areas through better product, while also driving service levels and improving store environment.
“Trading for the first five weeks of the third quarter is in line with the first half run rate, despite tougher comparatives. We believe we are well positioned for the all important Christmas period.”