In 13 young adult patients (5 men and 8 women) adult height was correlated with the average rachitic activity on radiographs of the wrist, taken at intervals during childhood. To this end the rachitic activity was classified into 4 different, clearly distinguishable stages according to its severity. The coefficient of correlation between adult height (expressed as standard deviation score) and the average rachitic activity or score was -0.796 (p less than 0.01), indicating that adult height varied inversely with the severity of the disease. The regression equation between adult height (y) and the rachitic score (x) was: y = -1.53x + 0.90; the SEy was 0.76. Although the coefficient of correlation was highly significant, this value for SEy indicated that much of the observed variation was due to other factors, apart from the rachitic process.