Ontario's premier's office says Jim Wilson has resigned his cabinet post to "seek treatment for addiction issues."
A spokesman for Premier Doug Ford says Wilson's resignation as minister of economic development, job creation and trade is effective immediately.
Wilson has also quit caucus.
Just hours before his resignation was announced, Wilson appeared with Ford at an event at a border crossing near Sarnia, Ont.
The two were photographed alongside two other Tory politicians in front of a sign advertising Ontario as "Open for Business."
Government House Leader Todd Smith will take over the portfolio in the interim.
Wilson, 55, who represents the riding of Simcoe-Grey on Georgian Bay, was first elected in 1990. When the Progressive Conservatives swept to office in 1995, Wilson was appointed minister of health and later became the energy, science and technology minister. He served under then-premier Ernie Eves in various portfolios, including briefly in environment.
