The incidence of diarrhea and enterotoxigenic Escherichia coli (ETEC) infection was evaluated in children six months to five years of age from an urban community in Jakarta, Indonesia. From January through May 1994, 408 children were monitored in their homes for diarrheal disease. Thirty-six percent (148 of 408) of the study children had at least one episode of diarrhea during the study period. Twenty-nine (19.6%) of the 148 children with diarrhea had ETEC isolated from a rectal swab sample at least once during the surveillance period; five children had ETEC isolated from two distinct episodes of diarrhea, giving a total of 34 episodes of ETEC positive diarrhea in the study group. Ten of 34 episodes were associated with heat-labile toxin, 15 of 34 with heat-stable toxin, and seven of 34 with both toxins. The mean age of children with diarrhea (1.7 years), whether ETEC positive or negative, was significantly lower than those who did not have diarrhea (2.4 years) during the study period; 82% of the children with ETEC were less than two years of age. This study demonstrates a high incidence of ETEC diarrhea among young children in Jakarta, and suggests this site would be suitable for ETEC vaccine efficacy trials.