The actors will get back into character as Inspector Robbie Lewis and his partner DS Hathaway for four new episodes, due to be filmed in July.
The new commission of the drama comes after series three, which was broadcast this spring, attracted seven million viewers, the channel said.
The series, an ITV Studios production, is produced by Chris Burt who has been at the helm of all 12 episodes since its launch in 2006. The executive producers are Michele Buck and Damien Timmer.
Sally Haynes, ITV's controller of drama commissioning, said: "Lewis is always one of the highlights of the year on ITV1 and features not only a great partnership between Lewis and Hathaway but some great plot lines and twists that keep the audience gripped. I'm thrilled it's returning and I know our viewers will be too."