Objectives: To report the nutritional status of children aged up to 15 years and their mothers living in a remote Amazonian area of Bolivia, and to study its main social, familial and maternal determinants. Setting: Fifteen Beni River communities located at the foot of the Andes. Design: Cross-sectional survey of riverside populations. All childbearing mothers and their children in the 15 communities were examined. Methods: Information on household production, dietary habits and demography was collected. Individual clinical, anthropometric and parasitological examinations were carried out. Subjects: A total of 631 persons were examined: 171 mothers and 460 children and adolescents aged 0 to 15 years. Results: There were no cases of severe wasting, but 41% of 0–5-year-olds and 36% of 5–10-year-olds were stunted. Among 346 stool specimens examined, 75% were positive for at least one helminth. Diversity of food and quality of diet were satisfactory in 54% of households, but 27% had low diversity scores. Mothers were lighter and shorter than those observed at the national level: 20% had height below 145cm. Prevalence of anaemia (42%) was also higher. In pre-school children, multivariate analysis indicated a relationship between growth retardation and household factors such as dietary quality, ethnic group and clinical state, but not maternal anthropometry. In contrast, in school-age children and adolescents, growth retardation was related to maternal characteristics. Conclusions: Growth retardation appeared mainly during the weaning period and did not seem to improve thereafter. To ameliorate this situation, an effort should be made to prevent common parasitic and infectious diseases in young children. Follow-up of pregnant mothers during pregnancy and delivery also needs to be reinforced