Introduction: Anxiety sensitivity (AS) refers to the fear of anxiety-related sensations due to beliefs that these sensations will lead to catastrophic outcomes. AS plays a central role in the etiology and maintenance of anxiety disorders. From a clinical perspective, it therefore seems important to possess a valid scale to assess AS in children. Objective, Method: This study examines the factor structure, reliability, and validity of the French translation of the Childhood Anxiety Sensitivity Index (CASI) in 353 Belgian children (9 to 13 years). Result: Results show that AS can be adequately measured using the French version of the CASI and conceptualized as a hierarchical factor structure with four lower-order factors–Physical Concerns, Mental Incapacity Concerns, Social Concerns, and Losing Control Concerns–loading on a single higher-order factor, Anxiety Sensitivity. The reliability was acceptable for the total scale. Hierarchical multiple regressions show that the CASI makes a significant contribution in predicting anxiety. Conclusion: The data support the relevance of the French CASI in the assessment of AS in nonclinical children.