This study investigated risk factors for acute lower respiratory infections (ALRI) in young Kenyan children. Exposures included mild-moderate malnutrition, household crowding, and low parental literacy. The study population consisted of 106 toddler-aged children (18-25 months) who were free of ALRI for at least 4 weeks before beginning a 1-year follow-up period. Subjects were visited weekly for morbidity information and monthly for anthropometric measurement. Being underweight (weight-for-age < 80 per cent of expected) was positively associated with ALRI, as was stunting (height-for-age < 90 per cent of expected). No association was found for acute wasting (weight-for-height < 90 per cent of expected). Having more than five siblings or parents with low reading skills were also risk factors. These data suggest that improving nutrition and parental literacy may contribute to lowering the incidence of acute lower respiratory infections. Interventions include breastfeeding, full immunization, diets adequate in quality and quantity, and early treatment through parental recognition of serious infections.