Blood pressure (BP) in children may increase more during puberty. Using a cohort of children where BP and body size had been closely monitored, we compared the rates of change in BP during the 3 yr period before puberty, during puberty (4.5 yr period), and the 3 yr period following puberty. Since there was no specific staging information with respect to puberty, we used pubertal growth (PG) as a surrogate of puberty. That latter was determined from serial measurements of height. All subjects (n = 151) were followed from before the period of PG to the period after PG; none were related. An age-dependent increase in systolic BP in the pre-PG period was similar regardless of sex or race. During PG, systolic BP in males increased 3 to 6 times faster than in the pre-PG period. In females, systolic BP increased less then in males during PG, but still increased 2 to 4 times faster than in the pre-PG period. The increase in males was significantly greater than in females (P < 0.001). Post-PG changes in BP were similar to changes in pre-PG BPs. In summary, PG was associated with profound increases in systolic BP. There were noticeably greater increments in males than in females consistent with the emergence of the well known sexual dimorphism in BPs.