The microbiological and morbidity profiles of acute diarrhoeal episodes were studied in 881 patients seen at the Out-Patients Department of the University of Calabar Teaching Hospital (UCTH), Calabar, between January and December, 1988. Of a total of 108 (12.3%) culturally confirmed bacterial diarrhoeas, 47 (43.5%) were due to Escherichia coli, 33 (30.6%) to vibrios (Vibrio cholerae-01; classical and E1 Tor biotypes and V. parahaemolyticus), while shigella spp. and salmonella. spp. accounted for 29 (17.7%) and 9 (8.3%) episodes respectively. Twenty (64.5%) of the patients with vibrio diarrhoeas were children less than or equal to 10 years. The only case of diarrhoea-associated death observed, involved an 8-month old infant with kwashiorkor and V. parahaemolyticus infection. Bimodal peaks of cholera episodes occurred during the dry season and appeared to coincide with acute water shortage periods in the municipality. The significance of some prevailing ecological factors in stabilizing a focus of cholera and halophilic vibrio diarrhoea endemicity in this region is discussed.