The participants included adult, youth, and female offenders from minimum to maximum security facilities. The State-Trait Personality Inventory (STPI), the Anger Expression scale (AX), the Institutional Stressor Scale (ISS) and the Reaction to Institutions Scale (RIS) were administered to the study participants. The data indicated that with age increase the intensity of anger expression decreased, whereas anger control increased. Significant positive correlations were found between age and inmates ISS and RIS. Comparisons between ethnic groups showed no differences between blacks and whites except for anxiety and curiosity differences in the Hispanics. Gender differences manifested greater anger expression in males and single individuals as compared with married persons. The level of education also affected differences. Results indicate that inmates enter the institutions with personality characteristics that could affect their relationships with other inmates and prison staff. 1 note and 19 references