Spinal bone density of 41 girls with diet-induced amenorrhea (DA) was compared with that of the density of 22 subjects with premature ovarian failure (POF) of comparable age. The Z score values, as well as the estradiol levels, were not significantly different in the two groups. The duration of amenorrhea was significantly correlated to bone mass density in the DA population, especially when considering subjects with amenorrhea that had lasted longer than 20 months. A similar correlation between weight loss and BMD was evident. Although estradiol concentrations did not seem to be correlated to the Z score, FT3 and cortisol values exhibited, respectively, a negative and a positive correlation with spinal density. Cortisol seemed to act precociously, whereas FT3 acted later than cortisol.