The department store chain saw a 0.3 per cent rise in sales at stores open more than a year for the 26 weeks to 27 February and claimed it was winning market share.
In the equivalent period the year before the figure was 0.1 per cent.
Chief executive Robe Templeman said: "We are pleased with our first half performance which shows continued progress in delivering our strategy.
"In 2009 we were one of only a handful of retailers to increase sales, margins and profits and we have done so again in the first half of 2010.
"Against the backdrop of challenging trading conditions, we have delivered profit growth on a consistent basis for the past 18 months."
Meanwhile gross transaction value increased 1.7 per cent, compared with analysts' consensus forecast of up 1.5 per cent.
Debenhams, with nearly 160 stores in Britain and Ireland and more than 50 franchised outlets overseas, is shifting from low margin concessions by devoting more space to own-brand products.
In concentrating on own-brand products Debenhams enjoys improved margins which fuels higher profits overall.
The firm said its gross margin for the period was "significantly higher" than the previous year, while its Designers at Debenhams set-up had boosted figures.
Debenhams also predicted year-end net debt within the range of market forecasts.