The new scale, the Prison Behavior Rating Scale (PBRS), was modeled after the Adult Inmate Management System checklist (AIMS) in many ways. Study 1 involved the construction and derivation of the PBRS scale. The initial item pool for the PBRS was composed of 86 items, many of which were derived from AIMS. The PBRS items were field tested in seven Scottish prisons. A total of 890 inmates were rated by correctional officers familiar with them. Preliminary item analyses were conducted to identify and exclude problematic items. Next, a principal components analysis of the PBRS was performed. Results of Study 1 suggested that the PBRS could be shortened to 36 items that yielded reliable scale scores for three separate behavioral dimensions: Anti-authority, Anxious-Depressed, and Dull-Confused. Study 2 cross-validated the PBRS internal consistency estimates and examined other aspects of the scale's reliability and validity. The final PBRS is a 34-item scale that can be administered rapidly by prison officers; it does not require extensive training or detailed file reviews Preliminary evidence suggests that the PBRS provides a reasonably reliable and valid description of three major dimensions of disturbed behavior in inmates. 4 tables and 62 references