Study subjects included a group of inmates housed at the Intensive Confinement Center in Lewisburg, Pennsylvania, and a group of inmates in the Federal Prison Camp in Allenwood, Pennsylvania. Self-report questionnaires were administered to the subjects. The first questionnaire was given within 2 weeks of an inmate's arrival at the institution, and the second questionnaire was completed about 6 months later. Information was obtained on demographics, the institutional environment, and adjustment to prison. Inmates who described their environment as having ultra-masculine attributes were more likely to report negative adjustment patterns. Perceptions of gender were important in inmate adjustment, although perceived differences in the gendered nature of the prison environment did not influence inmate adjustment patterns differently in the two prison populations. The authors conclude that an inmate's ability to undergo pro-social adjustment--the goal of shock incarceration programs--may be inhibited if the environment emphasizes ultra-masculine values. Supplemental data on the reliability of gendered environment and coercion scales are appended. 77 references, 15 footnotes, and 3 tables