A national scope study was performed to test empirically the hypothesis that juveniles in adult jails have a suicide rate higher than that of juveniles in the general population. Random samples were drawn from all United States juvenile detention centers, all jails with an average daily population of at least 250 inmates, a 20 percent random sample of jails with average daily populations under 250, and a 6.8 percent random sample of adult lockups. Data were collected by mailed questionnaires, with an overall response rate of 77.4 percent. Statistically significant differences were found between the suicide rates of juveniles in adult jails during 1978 (12.3 per 100,000) and juveniles in the general population in 1977 (2.7 per 100,000); between juveniles in adult lockups (8.6 per 100,000) and juveniles in the general population; between juveniles in juvenile detention facilities (1.6 per 100,000) and juveniles in adult jails; and between juveniles in juvenile detention centers and juveniles in adult lockups. Results support the hypothesis that the rate of suicide among children held in adult jails and lockups is significantly higher than that among children in juvenile detention centers and children in the general population of the United States. (NRB)