This study examined the factor structure, reliability, and validity of the German translation of the Childhood Anxiety Sensitivity Index (CASI). A total of 1292 adolescents participated in the study. Analyses using the Schmid-Leiman solution showed the CASI to have one higher order factor and three orthogonal lower order factors. CASI scores correlated significantly with anxiety symptoms and with general difficulties. Hierarchical multiple regression showed CASI to make a significant contribution in predicting anxiety even after controlling for variance due to general difficulties, thus giving further support to the incremental validity of the CASI. The CASI is a potentially useful measure to include in longitudinal studies that examine the development of childhood and adolescent anxiety disorders.