The 29-year-old Lewis, who was 19 when he made his debut for the county, left Surrey for a five-year contract at Grace Road.
"It is nice to be back and I feel very comfortable about the move," said Lewis, who first packed his bags to take up with Nottinghamshire in 1991. "I think my best years are ahead of me. I'm fitter and stronger and more determined than ever and I would love to get my England place back as well."
Lewis' traumatic career has been dogged by illness and injuries. He has been given many chances by England without being able to secure the regular place his talent should have brought him.
Middlesex will have a new opening batsman next season, having signed the 26-year-old Australian Justin Langer as their overseas player. The left-handed Langer, who has played for Australia eight times, has 17 centuries to his name, five of which were double centuries.
The fast bowler Waqar Younis has been dropped by Pakistan for the first Test against West Indies starting in Peshawar on Monday. Paceman Aqib Javed and wicketkeeper Rashid Latif were also not included.