The owners of the Whitegate oil refinery in Cork, Phillips 66, have reached a deal to sell the operation to the Canadian-owned Irving Oil.
The future of the operation, including the jobs of around 290 full-time staff, had been in doubt since last October when Phillips 66 announced its intention to sell the refinery.
However, Irving has said it will continue full operation of the facility and maintain the existing workforce.
Whitegate is the only oil refinery on the island of Ireland and supplies up to 40% of the main products on the market.
It was privatised as a result of its sale by the State in 2001 to Phillips 66.
Irving is a privately-owned Canadian energy company, which operates Canada's largest refinery in Saint John, New Brunswick, Canada, as well as wholesale distribution and retail businesses.
Minister for Communications, Climate Action and Environment Denis Naughten welcomed the announcement.
He said: "The Government's position on the Whitegate refinery has always been that the continued operation of the refinery on a commercial basis is highly desirable from an energy security and economic perspective.
"In this regard, the Minister is very pleased with the positive outcome to the sales process," he added.
A Sales and Purchase Agreement between the two firms was signed today and the deal is expected to close by the end of September.
