Preschool-age rural Indonesian children were reexamined every 3 months for 18 months. An average of 3135 children were free of respiratory disease and or diarrhea at the examination initiating each of the six, 3-month follow-up intervals. Children with mild xerophthalmia (night blindness and/or Bitot's spots) at the start and end of an interval developed respiratory disease and diarrhea at twice (p less than 0.001) and three times (p less than 0.001) the rate, respectively, of children with normal eyes during the same interval, independent of age and anthropometric status (weight for length). The risk of respiratory disease and diarrhea were more closely associated with vitamin A status than with general nutritional status. These results may explain much of the excess mortality recently reported for mildly vitamin A-deficient children.