In the article entitled “Influence of age and disease severity on high resolution CT lung densitometry in asthma” by F Mitsunobu et al which appeared in the November 2001 issue of Thorax (2001;56:851–6), an error occurred in table 3 on 854. The heading to the first column which appeared as “MLD (HU) (R² = 0.0524)” should read “MLD (HU) (R² = 0.524)”.