Like-for-like sales in the UK were down 0.7% in the 13 weeks to 31 March. Total group sales, which include new and overseas stores, increased 0.8%.
Sales were hit by poor performance in its general merchandise division, which includes fashion and home, and fell by 2.8%.
M&S admitted performance across its clothing business was "mixed", as a number of areas were short of stock of best selling lines.
The decision to exit the technology market impacted homewear sales.
Food sales, however, increased 1% on a like-for-like basis, credited to more than 500 new products during the quarter and promotions such as its Valentine's Day dine in meal deal.
Sales in M&S's international business also fell 2%. The online business, however, increased sales by 22.8% in the period.
M&S also said its pilot stores with new branding and layout for its fashion brands are "performing well" and getting a good response from customers. The store overhaul will continue to roll out across the store portfolio and is due for completion by mind-2013.
Chief executive Marc Bolland said: "While the short term trading outlook continues to be challenging, we are focused on investing in line with our plan and are making strong progress against our goal of becoming an international, multi-channel retailer."
