The bout is part of UFC 157, which will be held at Honda Center in Anaheim, Calif. The Orange County (Calif.) Register reported the Lawler-Koscheck fight earlier Wednesday.
Lawler will compete at 170 pounds for the first time since April 2004, when he was knocked out in the second round by Nick Diaz at UFC 47.
The UFC 157 appearance also marks the first time Lawler will step inside the Octagon since October 2004, when he was submitted by Evan Tanner in the first round at UFC 50.
Lawler made his middleweight debut in that fight but was released by the promotion after that loss. As a professional, Lawler is 19-9 with one no-contest. He has knocked out 16 opponents.
Lawler, who has fought in Strikeforce since 2009, returns to UFC with a 1-3 record in his past four fights.
Koscheck (17-6) seeks to rebound from a split-decision loss to Johny Hendricks in May. He came up short in his bid to unseat welterweight champion Georges St-Pierre at UFC 124 in December 2010, losing the bout by a lopsided unanimous decision.