We are presenting evidence of subclinical extrapyramidal hemosiderosis in chronic cystic fibrosis (CF) by histological staining and quantitative analysis. Comparison was made between age-matched control (eight cases) and CF brains (14 cases). None of the CF patients had extrapyramidal or other focal CNS symptoms but showed an increased iron pigment, and four cases had a few dystrophic axons (DA) in pallidonigral areas. Histological stain revealed significantly increased iron pigment in pallidonigral and subthalamic nuclei (P<0.05, 0.01, 0.01, respectively). The pigment was located in astrocytes, macrophages, neuronal perikarya, and neuropils. The increase was directly proportional to age and numbers of DA in nucleus gracilis/cuneatus. As in previous reports [5, 22], the numbers of DA in nucleus gracilis/cuneatus were higher in CF (P<0.01) and varied directly with age (correlation coefficient 0.72). Quantitative analysis disclosed an upward trend of mean iron content in pallidonigral areas. Aluminum was detected in four cases of CF but not in the controls.