Mushtaq Ahmed has decided to quit playing for Sussex due to a persistent knee injury.
The former Pakistan leg-spinner made the announcement on the club's official website.
Mushtaq has spent the last six years with Sussex and has played a major part in the county's success during that period, taking 598 wickets in all competitions.
In his time, Sussex have won three County Championships, as well as the C&G Trophy and the Totesport Division Two title.
Commenting on his decision to retire, Mushtaq said: "This is a very hard decision for me to make, as I feel that I could possible play one more year, but out of respect, I would only do that if I felt 100 per cent and I wouldn't want to risk that for the family.
"I am going to miss playing for the club greatly. I am truly honoured to have spent six wonderful years here."
Sussex cricket manager Mark Robinson said: "I don't think that it will ever be possible to overplay the enormous influence Mushtaq has had on Sussex in recent years.
"His record as a player and the trophies that he has helped us win will speak for itself, but I would like to pay tribute to him as a person from myself and all the people whose lives he has touched for the enormous influence he has had on us."
Sussex captain Chris Adams added: "Mushtaq's legacy at the club is that he leaves us statistically, romantically and emotionally the best player to ever pull on a Sussex shirt.
"In view of the impact he's made, it's difficult to think of another cricketer who has achieved or done more for one county."
