The current study evaluates the extent of prior drug use and psychosocial dysfunction related to drug use among 499 jail inmates referred to the Hillsborough County Sheriffs Office Substance Abuse Treatment Program. Results indicate that inmates were involved with drugs for an average of more than 7 years, and with cocaine for almost 5 years. The majority of inmates reported extremely heavy use of drugs in the month prior to the last arrest, including 83% that had used cocaine. Many drug-dependent inmates reported a shift over time from intranasaf to freebase cocaine use. Half of all referrals indicated a pattern of regular use within a year of involvement with drugs. The need for lengthy, heavily structured, and intensive treatment approaches for drug-dependent jail inmates is underscored by a history of chronic cocaine and polydrug abuse, a compulsive pattern of drug use, few successful periods of voluntary abstinence, and severe disruption in vocational, social, and psychological functioning. Their history of infrequent and unsuccessful involvement in rehabilitation programs reflects a significant need for compulsory treatment following release from jail, community supervision to ensure compliance with treatment, and development of linkages between jail drug treatment programs, courts, and community treatment providers.