Prisoners are reported to have a higher suicide rate than the community. We studied suicides in the Maryland prison system to determine the level of risk and risk factors for inmate suicide. There were 37 male inmate suicide deaths between 1979 and 1987 (39.6 suicides per 100,000 male inmates), which is significantly higher than the age- and race-adjusted male suicide rate in the general population of Maryland (22.0 per 100,000). Risk of male inmate suicide was increased for the following characteristics: white race (relative risk [RR], 2.0; 95% confidence interval [CI], 1.1 to 3.9), age 25 to 34 years (RR, 1.8; 95% CI, 1.0 to 3.4), major crime committed against person (RR, 3.4; 95% CI, 1.7 to 6.7), life sentence (RR, 4.7; 95% CI, 2.2 to 10.0), and classification to the major maximum security institution in the prison system (RR, 5.1; 95% CI, 2.7 to 9.8). The methods of suicide chosen by inmates were hanging (86%), cutting wound (5%), antidepressant overdose (5%), and fall from height (3%). We conclude that inmate suicide represents a significant correctional health and public health problem. Specific implications for prevention of inmate suicide are examined.