The original TCU Drug Screen was developed at the Institute of Behavioral Research at TCU and has shown promise in meeting the substance abuse diagnostic needs of large correctional systems. It has been used since 1993. Revised twice since its earlier version (called the Brief Background Assessment), the current TCU Drug Screen includes 19 items that represent key clinical and diagnostic criteria for substance "dependence" as they appear in the Diagnostic and Statistical Manual and the National Institute of Mental Health Diagnostic Interview Schedule. These criteria were adapted for use within criminal justice settings by rewording "clinical" language to be more appropriate for individuals with eighth-grade reading levels and by using a format that promotes reliable self-administration. For the current study, analyses of the instrument data were based on a cohort of 18,364 Texas Department of Criminal Justice inmates (15,816 males and 2,548 females) who completed the screen between January 1 and April 30, 1999. Although designed to be administered in a group or individual setting, the TCU Drug Screen was administered successfully by staff almost exclusively in a small group setting (12-25 inmates per group) across several facilities. The TCU Drug Screen was also found to have good psychometric properties, and normative responses for the overall sample and subgroups were documented. Based on feedback from interviewers and inmates, as well as the results of the analyses of the screen's psychometric properties, a revised screen, called the TCU Drug Screen II, was developed. 5 figures, 28 references, and appended TCU Drug Screen and TCU Drug Screen II