An uncertain relation between health and angry/hostile behaviour exists in the literature on adolescents. With data from a pilot study, one possible reason for this is explored: health measures such as blood pressure as well as angry/hostile behaviours may change with, or depend upon physical maturity, body size and body fatness. The sample consists of 60 African-, Hispanic-, and Anglo-American adolescents (15 to 16 years of age) drawn from a public school in Houston, TX. Using resting diastolic blood pressure as a model, in a sex stratified analysis, the following conclusions were reached: Physical maturity in girls and body height in boys were related to ethnicity in the sample and were confounders of the blood pressure and anger relationship. In girls secretive anger ('anger-in') and hostility were associated with increased body fat; expressive anger ('anger-out') in boys is associated with increased conicity (central body fat distribution) (p < 0.01). These associations were independent of height and physical maturity. Hostility was not significantly related to diastolic blood pressure in boys after adjusting for height and conicity. 'Anger-in' was significantly and positively related to diastolic blood pressure in girls (p < 0.01). This relationship was strongly mediated by per cent body fat, because the association of 'anger-in' and blood pressure was no longer statistically significant when the model included body fat. The results suggest that measures of physical maturity and more refined measures of body fat and body fat distribution should be considered in studies attempting to link adolescent blood pressure with anger expression.