BACKGROUND.: According to the World Health Organization, depression ranks as a major contributor to the global burden of disease. A large proportion of adult depressions had their first appearance in adolescence. Brief and reliable rating scales are needed for early detection. OBJECTIVE.: The aim of this study is to validate the WHO-5 and the HSCL-6 for detection of depression among adolescents. METHODS.: The project is a GP multicentre study conducted in Denmark and Norway. A total of 294 adolescents (14–16 years) responded by answering a paper- or web-based questionnaire and later completed a Composite International Diagnostic Interview, which was used as the gold standard. Depression was defined by ICD-10 criteria. Criterion validity was examined, the likelihood ratios measured and cut-offs for depression were calculated using the Youden index. RESULTS.: The prevalence of depression was 11.8% in our sample. The optimal cut-off point was 11 for the WHO-5 test and 9 for the HSCL-6 test. There were no gender differences. For the WHO-5 and the HSCL-6, respectively, the sensitivity was 0.88 [95% confidence interval (CI): 0.74–0.96] and 0.85 (95% CI: 0.70–0.94), the specificity was 0.80 (95% CI: 0.75–0.85) and 0.79 (95% CI: 0.74–0.84) and the likelihood ratio was 4.5 and 3.8 (P = 0.39). We observed no statistically significant diagnostic differences with respect to nationality or administration procedure. CONCLUSIONS.: The WHO-5 and the HSCL-6 may both serve as valid case finding instruments for depression in young people in primary care.