Mitt Romney has clinched the Republican presidential nomination with a win in the Texas primary.
He surpassed the 1,144 delegates needed to win the nomination by winning at least 88 delegates.
Mr Romney , who came up short in the Republican presidential race four years ago, outlasted a number of Republican rivals who dropped out of the state-by-state primary contest.
"I am honoured that Americans across the country have given their support to my candidacy and I am humbled to have won enough delegates to become the Republican Party's 2012 presidential nominee," he said in a statement.
"Our party has come together with the goal of putting the failures of the last three and a half years behind us.
"I have no illusions about the difficulties of the task before us. But whatever challenges lie ahead, we will settle for nothing less than getting America back on the path to full employment and prosperity."
Republicans will not officially nominate Mr Romney until late August at the Republican National Convention in Tampa, Florida.
He will face Democratic President Barack Obama in the November 6 election.
