This study replicates and extends studies of the Massachusetts Youth Screening Instrument, Version 2 (MAYSI-2) in a sample of 479 urban, rural, and suburban 12–16 year old youths (68% boys; 41% African American, 23% Latino) consecutively admitted to juvenile detention centers. Six principal components replicated the MAYSI-2 factor-analytically-derived subscales except for Depression/Anxiety, and suggested modifications of specific items in each sub-scale. Findings supported the internal consistency and validity of the modified MAYSI-2 sub-scales. Few gender differences emerged, except that girls reported higher levels of hopelessness and trauma than boys. Five sub-groups were identified based on component profiles: (1) non-clinical, (2) addiction, somatic problems, and suicidality, (3) anger problems, (4) thought disturbance, and (5) addiction and traumatic stress. The findings support the validity of the MAYSI-2 for juvenile justice mental health screening while highlighting possible refinements in scoring in order to identify delinquent youths with distinctive psychosocial risks and needs.