Lloyds Pharmacy is to add up to 60 new branches to Ireland with the creation of 500 new jobs.
The expansion plan is to be rolled out over a three-year period and will increase its total workforce to 1,500.
Its presence will grow from its 91 current stores to about 150.
The pharmacy chain, currently the largest in Ireland, has also decided to invest more than €2 million in a new patient services programme throughout existing outlets.
It had flagged its expansion ambitions last January following a strong sales performance over Christmas.
The chain added 14 outlets during last year, describing the year as “very positive” for sales and said it intended to build on its progress by introducing new products.
Services already offered include blood pressure testing, express prescription services, food intolerance testing, diabetes support and asthma control.
Management at the pharmacy has signalled its intent to expand into new communities, consolidating its dominant market position. Lloyds has already set about identifying new sites.