Although the possible role of hypertension and/or blood pressure variability in the causation of juvenile delinquency has not been directly investigated hitherto, there is evidence to suggest (a) that an excess prevalence of blood pressure variability rather than hypertension is the aspect of cardiovascular functioning which characterizes adolescents, and some indirect evidence suggests (b) that increased blood pressure variability rather than hypertension is associated with juvenile delinquency. Official criminal statistics reveal a marked increase in the rate of convictions of males in their early and middle teens--the time of puberty and the adolescent growth spurt. It is hypothesized that increased blood pressure variability is one aspect of the general change in growth rate and metabolism occurring at puberty. These physiologic changes, together with the simultaneous addition of various social stresses, may lower the threshold for aggression and impulsivity, thus placing the individual at greater risk of involvement in the wide spectrum of behaviors collectively termed "delinquent".