The Brooklyn district attorney developed and implemented the Drug Treatment Alternative-to-Prison (DTAP) in 1990. The program was expanded to Manhattan and Queens, N.Y. in 1992. DTAP targets defendants with prior nonviolent felony convictions and places them in highly structured therapeutic communities. It takes advantage of the severity of the charges to pressure offenders to stay in treatment. Defendants who fail in DTAP face severe, mandatory minimum prison terms of 1.5 years or more. The program also includes an enforcement component. Data from the program reveal that DTAP programs have retention rates that are at least 1.5 times higher than rates in comparable treatment programs. Sixty-five percent of the 463 persons admitted during the study period remained in treatment at the close of the reporting period. Retention rates are similar across the more than 24 treatment sites. Factors related to retention include being older, having more education, having a better employment history, less self-reported crime and drug offenses, no recent physical or emotional abuse, no history of psychological problems, and negative perceptions of prison. Figures, tables, footnotes, and 60 references