Medirest, Compass Group's healthcare division, has secured a 10-year contract, for an undisclosed sum, to provide café and retail services across Hywel Dda University Health Board.
The firm will introduce Costa cafes and amigo shops at Withybush, Glangwili, Prince Philip and Bronglais hospitals, with the addition of a Deli Marche at Bronglais.
Andrew Jones, retail operations director healthcare, Compass Group UK & Ireland, said: "We're looking forward to working with the Health Board across its four hospitals in Wales.
"We'll be implementing our trusted partner brands in these sites, bringing an enhanced service to patients, visitors and staff, as well as offer a source of income for the Health Board."
The new facilities will open in spring 2016.