The range will initially be trialled in the Blackpool, Cleveleys, Southport, St Helens and Whitehaven shops. If it proves successful, the range will be rolled out in the remaining 15 outlets over the next year.
The sandwiches, baps, rolls and tortilla wraps will be supplied by Blackpool-based Ashbury Sandwiches.
B& M chief executive Stuart Greenwood said: “We have discovered that customers want to be able to do their entire shopping under one roof.
“We have therefore planned to implement similar schemes throughout the year that will offer people that little bit more from a B&M Retail shopping experience.”