Measurements of anthropometry and total body water (TBW) were made in 99 women 19-44 y of age living in socioeconomically deprived circumstances in Cali, Colombia. TBW was measured by dilution of deuterium oxide. An empirical equation for estimating lean body mass (LBM) was derived and applied satisfactorily to an independent study group. Comparisons were also made with body-composition values obtained by the Durnin and Womersley equations and an equation derived from rural women living in Guatemala. Neither set of equations was suitable for use with the Colombian subjects because both significantly overestimated LBM and therefore underestimated body fat. Lower values of standing height in older women suggest that they may have been subjected to more severe undernutrition during their growth than the younger subjects. When compared with a group of US women, Colombian subjects were less physically fit and had greater subcutaneous-fat deposits, which were distributed over the trunk and limbs, whereas body mass indexes and waist-hip ratios were not significantly different.