The 25-year-old Giddins was released by Sussex when he tested positive for cocaine this summer and as many as 10 counties were said to be interested in signing him.
Warwickshire believe the player, who will be paid a retainer to take part in midweek net practice while he plays league cricket in the south next year, is determined to get his career back on track.
"He realises he has made a mistake. That's all behind him now," the Warwickshire chief executive, Dennis Amiss, said.
"He'll have served his penalty by the time he comes to us in 1998. He's really focused and has convinced us that cricket is his future. He wants to play and do a good job for Warwickshire but he also wants to go on and play for England. I believe that Warwickshire can help him do that.
"He will strengthen our squad and we look forward to seeing him with us for the 1998 season."
Giddins, who lost his appeal against the ban 10 days ago, said: "Deciding to join Warwickshire was a hard decision for me but just walking in at Edgbaston I felt a buzz. They have been the most successful side over the last three or four years and there's no reason why that shouldn't continue."
Giddins, who was on the staff at Sussex for six years, decided to join Warwickshire after a series of meetings with the county.
The England leg-spinner Ian Salisbury has rejected the best offer Sussex have ever made to a player and has joined Surrey on a three-year contract. Salisbury, 26, had been at Hove for seven years and decided to move on despite Sussex's offer of a five-year contract with the promise of a benefit.
Secretary Nigel Bett said that "every effort" had been made to change Salisbury's mind. He added: "Ian has kept us fully aware of his plans and there has been no disagreement between the club and himself. Now that his future is settled we must plan for 1997 without him."Reuse content