The former 'Partridge Family' star has been ordered by a judge to complete a three-month rehab and a five-year probation following his DUI arrest in January this year after he made an illegal right turn against a red light, reported TMZ online.
He allegedly had a blood alcohol level of more than twice the legal limit.
Cassidy, 63, has been fined as well and is required to complete a nine-month alcohol education program.
The former teen star was previously charged for DUI in Florida in 2010 and later in upstate New York in August last year. The DUI case in New York was reduced from a felony to misdemeanour earlier this month.