The Mood and Feelings Questionnaire (MFQ) is examined for its utility in screening youth in juvenile justice settings for depression. In a cross-sectional study conducted at King County Juvenile Detention Center, a representative sample of 228 detained adolescents complete structured assessments, including the MFQ and the Massachusetts Youth Screening Instrument. Fifty youth also complete the Voice-Diagnostic Interview Schedule for Children. Internal reliability coefficient for the MFQ short form (SMFQ) is = .87. Factor analysis produces a unifactorial scale with item loadings of .43 to .78. At SMFQ cutoff 10, sensitivity and specificity are optimized at 1.00/0.79. Prevalence of major depressive disorder is estimated at 32.1% (95% Confidence Interval = 25.3% to 39.2%). The SMFQ shows potential for depression screening of detained adolescents.