Loss of height with advancing years in women most commonly reflects the development of osteoporosis of the vertebral column. Moreover, height measurement from young adult life is often not available for making this judgement about a particular woman. Unless affected by fracture or Paget's disease of bone, alteration in hip length with age is unlikely. We have therefore examined the relationship between height and hip length in young adult Caucasian Australian women and used this to predict earlier 'maximal height' from hip length in elderly Caucasian Australian women. The equation used was maximal height = a + b hip length (r = 0.65, n = 36, P less than 0.0001) where values for a and b were taken from the sample of young women, (a = 1.096, b = 1.185) and applied to the older women. The difference between 'maximal height' and 'observed height' then provided an estimate of 'loss of height'. For a representative sample of ambulant institutionalized elderly women aged 85 +/- 6.47 years, (mean +/- s.d.) range 70-98 years, the loss of height was 0.15 +/- 0.07 m (mean +/- s.d.), range 0-0.27 m. For such groups of women there should be value in knowing maximal height and loss of height at least in so far as assessment of lean body mass, adiposity (as BMI or weight (kg)/height(m)2) and osteoporosis are concerned.