Waitrose has seen sandwich sales rocket up 11% compared to this time last year.
The retailer said total sales were up 0.3% on the same period last year, in the week to 16 May.
Salads were also up 24% in sales, and packs of snacks up 49%.
Waitrose has also launched a new range of lunch options into its Good to Go range, taking inspiration from American, Mexican and Indian cuisines.
The range includes the Cheese Steak Roll with Paprika Mayo at £3.20 and Waitrose Smoked Turkey & Mustard Slaw with Gherkins sandwich at £2.80.
The retailer said: “Mexican food is another trend which continues to thrive.”
It also added that it was still seeing significant deflationary impact across categories, for example iceberg lettuces and 1kg bags of carrots, which are each selling for 60p, compared to £1 this time last year.