Over a period of 12 months, a total of 852 stool samples from patients (both children and adults) with acute diarrhoeal diseases attending some public and government recognised health institutions in Lagos metropolis were screened for diarrhoeagenic bacterial agents. One hundred and eighty two bacterial isolates were found out of which 83 (45.6%) were Escherichia coli, 38 (20.9%) Shigella spp, 31 (17%) Salmonella spp, 16 (8.8%) Klebsiella spp, eight (4.4%) Aeromonas spp, while there were only six (3.3%) isolates for Plesiomonas spp. Of the 83 isolates for E. coli group, 49 (59%) were enteropathogenic (EPEC), 17 (20.5%) enterotoxigenic (ETEC), 10 (12.1%) enteroinvasive (EIEC) and seven (8.4%) enterohaemorrhagic (EHEC). The EPEC strains particularly serotype 055, were mostly encountered in children aged over five years. On the other hand, EIEC and ETEC strains were found mainly in adults while EHEC O157: H7 strains occurred in all the age groups studied. This study further stresses the important role of EIEC and ETEC in acute diarrhoeal diseases and the possible implication of EHEC in acute gastroenteritis, especially in children in Lagos, Nigeria.