In a preliminary study, nine children aged 6 to 12 years, with affective disorders, were studied during a two- to three-week hospitalization. Biochemical as well as behavioral data were collected. The urinary metabolites studied were norepinephrine, vanillymandelic acid, and 3-methoxy-4-hydroxyphenylethyl glycol. Deviations from values in normal controls were found in all the children, but were most apparent in those with chronic affective disorders. This suggests that clinical investigation of the biology of such childhood disorders may be relevant for issues of cause or treatment as they have been in adult affective disorders.