The company said it had been planning further moves into Continental Europe since its acquisition in February 1992 of Brossette, France's leading plumbing distributor.
The purchase of OAG from Wienerberger of Vienna, one of Austria's largest quoted companies, gives Wolseley the number one slot in that country's plumbing distribution market.
OAG, founded in 1871, operates from 40 locations in Austria and has branches in Germany, Hungary and the Czech Republic.
Profits of pounds 9m in the year to December were struck from sales of pounds 187m. Net assets were pounds 18.2m.
The acquisition of OAG follows two similar-sized purchases last year. In April, Wolseley paid pounds 56m for Enertech, a Swedish manufacturer of oil and gas burners. It spent a further pounds 52m in August on Erb, a US lumber distributor.
Both contributed to an 83 per cent increase in pre-tax profits for the six months to January. The pounds 87m return was well ahead of market expectations of pounds 65m- pounds 70m.
The shares closed 1p higher at 894p.