OMV had put the network up for sale as part of a divestment plan aimed at raising 2 billion euros to help fund a deal making it the majority owner of plastics maker Borealis.

EG Group was founded by the billionaire Issa brothers who are buying British supermarket chain Asda from U.S. retail giant Walmart.

"This marks a further step in our previously announced 2-billion-euro divestment program and this transaction will reduce OMV's debt by approximately half a billion euros at the time of closing," OMV Chief Executive Rainer Seele said in a statement.

The petrol stations are in the German states of Bavaria and Baden-Wuerttemberg. OMV also has a refinery in Burghausen in Bavaria but it said there was "only a very limited degree of integration" with its German petrol stations as the refinery focuses on producing petrochemicals rather than petrol.

"The purchase price amounts to 485 million euros. As part of the agreement, EG Group will assume outstanding lease liabilities resulting in a total enterprise value for the business of approximately 614 million euros," OMV said.

($1 = 0.8230 euros)

(Reporting by Francois Murphy and Alexandra Schwarz-Goerlich, editing by Louise Heavens and Gareth Jones)