Escherichia coli isolated from 389 children, less than 1-year of age with diarrhoea, were analyzed for the presence of Enteroaggregative E. coli (EAggEC) by their pattern of adherence to HeLa cells. EAggEC were isolated from 58 (14.8%) children either as a sole pathogen or in combination with other enteric pathogens. In 60% of these children EAggEC infection occurred in the second half of infancy (7-12 m). Thirty-eight of 47 children having EAggEC as a sole pathogen had watery diarrhoea along with vomiting (87%) and dehydration (74%). In contrast, 9 of the 47 cases had mucoid diarrhoea with infrequent vomiting and dehydration and frequent abdominal pain. Children infected with EAggEC were successfully rehydrated with oral rehydration solution (ORS) alone. Seventy-one percent of the EAggEC strains were resistant to more than three antibiotics. It was evident by phage pattern that various EAggEC strains were present in the population. The results indicated that infections with EAggEC may have a role in the development of diarrhoea among children less than 1-year of age in Bangladesh.