Patrick Enebeli Osakwe was elected to the National Senate for the Delta North constituency in 1999. In October 2002, when there was a movement to impeach President Olusegun Obasanjo, he said that senators should not sign the impeachment document without first consulting their electorates. Shortly before the April 2003 elections, Osakwe denied being among the senators who endorsed the amendment of the Independent Corrupt Practices and other related offences Commission (ICPC) Act.
He was reelected in 2003 as candidate for the People's Democratic Party (PDP), despite a poor reputation for contributing to debates or motions in the upper chamber. He was elected again in 2007 representing the Accord party. He was appointed to committees on Gas, Banking, Insurance & Other Financial Institutions, Appropriation, Niger Delta and Senate Services.
In a January 2008 debate over the proposed Freedom of Information Bill, Osakwe asked why the bill was not signed by former President Olusegun Obasanjo. He noted that the act had to comply with the Official Secrets Act.
In May, 2008 the Election Petition Tribunal in Asaba struck out a petition against the election of the Governor of Delta State, Emmanuel Uduaghan and Patrick Osakwe. The PDP candidate Mirian Comfort Ali had asserted that the Accord party did not validly present Patrick Osakwe as candidate for the election.
In July 2009, Osakwe, Deputy Chairman of the Senate committee on Gas, condemned the "over involvement" of the Federal Government in the oil and gas sector at a Delta State meeting to discuss the National Gas Master Plan.