Malik will arrive at Old Trafford ahead of their opening game of the Friends Provident Twenty20 tournament on June 4 at Durham Dynamos, a statement in Lancashire's official website said.
Malik, who married Indian tennis ace Sania Mirza [ Images ] last month, is without international commitments as he is serving a 12-month ban imposed on him by the Pakistan Cricket Board after being accused of disrupting team morale during the disastrous tour of Australia [ Images ].
The 28-year-old all-rounder has featured in 30 Twenty20 Internationals for his country so far and has scored 603 runs with an average of 26.21. With the ball, he has taken 14 wickets, recording a personal best of two for 14.
"When Lancashire approached me to come and play for them I didn't hesitate in saying yes. I love playing cricket in England [ Images ] and the opportunity to play with a club of Lancashire's reputation was too good to pass up," a delighted Malik said.
"Their recent overseas signings in Katich and Chanderpaul only add to an already strong list. I am very excited and look forward to a strong T20 campaign," he said.
Lancashire Cricket Director Mike Watkinson said, "We are delighted to recruit yet another world class player to the cricket club. Shoaib (Malik) will be a quality addition to our T20 squad.
"Shoaib has a proven track record in the game and is a versatile cricketer. He's at a good age, can bat up and down the order and is an experienced spin bowler," Lancashire head coach Peter Moores added.