The effect of anxiety (measured by the state-trait anxiety inventory) on resting regional cerebral blood flow (rCBF) (measured by the 133-Xenon inhalation method) was studied in 38 female and 37 male patients undergoing rCBF examination for the first time. Significant negative correlations were found between anxiety and rCBF. This could contribute in understanding rCBF variability in the so-called "resting condition".