AbstractObjectiveTo determine the prevalence and factors associated with stunting in 6-month-old South African infants.DesignThis cross-sectional study was part of the baseline of a randomized controlled trial. Weight-for-length, length-for-age and weight-for-ageZ-scores were based on the WHO classification. Blood samples were analysed for Hb, plasma ferritin and soluble transferrin receptor (sTfR). Socio-economic, breast-feeding and complementary feeding practices were assessed by questionnaire.Setting/SubjectsInfants aged 6 months (n750) from a peri-urban area of Matlosana Municipality, North West Province of South Africa.ResultsStunting, underweight, wasting and overweight affected 28·5, 11·1, 1·7 and 10·1 % of infants, respectively. Exclusive breast-feeding to 6 months of age was reported in 5·9 % of the infants. Multivariable binary logistic regression showed that birth weight (OR=0·12; 95 % CI 0·07, 0·21,P<0·001) and maternal height (OR=0·94; 95 % CI 0·91, 0·98,P=0·001) were inversely associated with stunting; while male sex (OR=1·73; 95 % CI 1·10, 2·70,P=0·014) was associated with higher odds for stunting. Stunting was also associated with higher plasma sTfR (>8·3 mg/l) concentrations.ConclusionsThe association between stunting and lower birth weight, shorter maternal height and male sex reflects possibly the intergenerational origins of stunting. Therefore, interventions that focus on improving preconceptual and maternal nutritional status, combined with strategies to promote appropriate infant feeding practices, may be an important strategy to prevent stunting in vulnerable settings.