Background and objective. The deuterium oxide (do) dilution method for measuring body composition was validated against the widely used skinfold (sf) measurement-based equation of durnin and womersley. The study involved 10 lactating women living in a rural community in nandi, kenya and participating in a cross-sectional study aimed at determining their iron and vitamin a status.methods. The selection criteria were exclusive breast-feeding, infants between 2 and 4 months of age, maternal parity <4, birth weight more than 2 500 g and no congenital abnormalities. Maternal and infant anthropometric measurements were taken. Do (approximately 0.1 g 2h2o/kg body water) was given orally to each mother accordingly to the maastricht protocol (do) for total body water (tbw) determination. The 2h enrichment of the urine was measured using gas-isotope-ratio mass spectrometry. Blood samples were collected. Serum retinol and ferritin were determined using high- performance liquid chromatography (hplc) and enzyme-linked immunosorbent assay (elisa) respectively. Body mass index (bmi) was determined as weight/height (m2). The bland-altman pair-wise comparison was used to compare maternal fat-free mass (ffm), body fat (bf) and percentage body fat (% bf) that were determined based on the do and sf techniques.results. Maternal mean (± standard deviation (sd)) for parity, age, bmi, haemoglobin (hb), serum ferritin and serum retinol were 3 (2), 26 (4) years, 23.4 (4), 12.1 (1.8) g/dl, 10.3 (4.0) µg/l and 0.696 (0.300) µmol/l respectively. The ffm, bf and % bf accordingly to the do and sf methods respectively were 44.0 (4.7) kg v. 42.9 (5.9) kg, 16.7 (8.8) kg v. 17.8 (7.5) kg and 26.2 (8.1)% v. 28.4 (6.4)%. Limits of agreement for underestimation of ffm and % bf were 4.4 kg (see 3.4) and 11.6% (see 5.8) respectively. Bias in the measurement of ffm and % bf was 1.1 kg (see 1.9), and —2.2% (see 3.3) respectively.conclusion. The variability (5.8 - 17.5%) observed in the sf technique may result in lower prediction of % bf. This may be an important factor for community-based nutritional interventions that aim at improving the body composition of vulnerable groups such as pregnant and lactating women or subjectswith severe undernutrition.