The relationship of relative body weight (RBW) and adiposity to blood pressure and blood lipids was studied in a selected group of adolescents aged 15-17 years with RBW between 95 and 140 per cent and body fat tissue between 10 and 45 per cent. The increase in RBW and percentage of body fat was positively associated with systolic blood pressure in boys and girls and with diastolic blood pressure in girls. In boys, the RBW and percentage of body fat were also positively associated with total lipids, VLDL and negatively associated with HDL. In girls, there was a positive association of RBW and body fat with blood cholesterol, total lipids and LDL-cholesterol. These associations, though statistically significant, were of a rather low order when the entire range of body mass and percentage of body fat distribution were considered, but became more significant in more extreme distribution categories. The results indicate that the increase of RBW over 25 per cent of standard in both boys and girls as well as the increase in percentage of body fat over 25 per cent in boys and over 35 per cent in girls may be associated with elevated blood pressure and changes in blood lipid values in adolescents.