A longitudinal study of diarrhea was carried out from May 1988 to April 1989 by household surveillance of 705 children Shigella species (P =.07) and rotavirus (P < .05). Diffusely adherent Escherichia coli (P < .05) and cryptosporidia (P = .07) were the only enteropathogens associated with persistent diarrhea in comparison with acute diarrhea. No more than 15% of children had the same class of pathogen identified from stool on both days 1–3 and days 15–17, indicating that persistent infection was uncommon. However, a different enteropathogen was frequently found on days 15–17, suggesting that sequential infection may be a cause of persistent diarrhea.