Human infections caused by Aeromonas spp. are being reported with increased frequency. We examined 1012 unselected stool specimens from 799 children for various pathogens, including Aeromonas spp., to evaluate the clinical associations of Aeromonas spp. in the stools of children in the East End of London. A total of 33 children had positive cultures for Aeromonas spp. These were identified as: Aeromonas hydrophila (16), A. sobria (9), A. caviae (8). Aeromonas spp. were identified by being oxidase positive in character, a property that distinguishes Aeromonas spp. from Enterobacteriaceae. Associated pathogens included Salmonella typhimurium (1), Campylobacter spp. (3), Enteropathogenic Escherichia coli (2), and Giardia lamblia (1). Electron microscopic examination of the stool of 13 children revealed viral particles in two, rotavirus (1), and coronavirus-like particles (1). The associated clinical features in the 25 children with only Aeromonas excretion were diarrhea (21), vomiting (10), abdominal pain (9), fever (4), and mild dehydration (2). Five patients had macroscopic blood loss in the stools. The illness was generally mild and lasted only a short time.