The child version of the Carver and White (1994) BIS/BAS-scales (Muris et al., 2005) was used to assess sensitivity of the Behavioral Inhibition and the Behavioral Activation System in clinically anxious and non-anxious youth (n = 175, ages 8-18 years, 70 boys). Results supported the hypothesis that clinical anxiety is associated with overactivity in the BIS (Gray, 1982). Consistent with the revised Reinforcement Sensitivity Theory (Gray and McNaughton, 2000 J.A. Gray and N. McNaughton, The neuropsychology of anxiety: An inquiry into the functions of the septo-hippocampal system, (2nd ed.), Oxford University Press (2000). Gray & McNaughton, 2000) the BIS-scale consists of two subscales, one measuring BIS_Anxiety and one measuring FFFS_Fear. BIS-scores were higher in the anxious sample than in the non-anxious sample. BAS-scores were equal. Higher levels of BIS-activity were related with an increase in symptoms of anxiety and depression. BIS-scores were higher in girls than in boys, there were no gender differences in BAS-scores.