Kingfisher has unveiled plans for 80 Polish stores, coinciding with last weekend's enlargement of the EU.
Poland joined the EU on May 1, along with nine other countries. Kingfisher chief executive for international and development Ian Cheshire described Castorama Poland as 'one of the gems of the Kingfisher portfolio'.
Poland is the only accession country in which Kingfisher has a presence.
Its 19 Castorama stores will rise to 26 by next February, with an eventual target of 80 shops.
Kingfisher's main rival in Poland is Metro-owned Praktiker, which has 16 stores.
Cheshire said: 'People here see EU accession as a long-term positive for Poland, feeling it will accelerate and strengthen the development of the economy.'
However, he warned that the Poles were not 'overly romantic' about prospects, and improvements to infrastructure could take time.
EU accession meant that 10,000 prices needed to be altered in stores overnight, and tills upgraded to accept euros. Cheshire said planning regulations would become tougher, but would still be more relaxed than in the UK and France.
A smaller store type, two-thirds the size of the 9,000 sq ft (835 sq m) Polish Warehouse stores, is being tested.
A Tesco spokesman said there were 'undoubted benefits' to EU enlargement for the new member states where it has a presence, including Poland, Hungary, the Czech Republic and Slovakia.
Metro, which occupies 134 shops in the same accession territories as Tesco, said expansion would provide a 'new impetus for growth'.