"I'm very pleased to have the chance to meet with our employees here," said Barra, who became GM's CEO on January 15 this year.
"I thought it was very important to reinforce in person GM's commitment to Opel, its importance to the company and the need to accelerate our progress going forward.
"I am also pleased to confirm that we will add another model to our Rüsselsheim plant. With Dan Ammann nominated to succeed Steve Girsky as Chairman of the Opel Supervisory Board and with KT Neumann leading the Opel team, I'm confident that we can achieve our goal to break-even in Europe by mid-decade."
Barra noted that GM is investing €4bn in Germany and Europe through 2016, which will help bring 23 new products and 13 new engines to market.
"We must remain focused on the customer and delivering great, innovative products to the market on a consistent and sustained basis," she said. "That is how we will win here and all around the world."
During her visit, Barra toured the Rüsselsheim plant, home to 3,300 employees and where the Opel Insignia and Astra models are built.
She also visited the ITDC, GM's second largest development centre in the world, where more than 6,000 engineers, technicians and designers are working on the latest technologies for future GM vehicles.
Opel CEO Dr Karl-Thomas Neumann said the Opel team was thrilled to have hosted Barra and Ammann: "We are honoured that Mary and Dan chose Opel as the first GM location to visit outside the company's Detroit headquarters. It reinforced for all of us the importance of Opel to GM and the support we will continue to receive as we drive to return Opel and its products to greatness."
