Leucocytes have the capacity to respond to chemotactic factors by becoming morphologically and functionally polarized and this method has been found to be suitable for measurement of chemotaxis. This work evaluates the effect of whole Vibrio cholerae biotype El Tor polarization of human polymorphonuclear (PMN) cells in comparison with strains of V. cholerae NAG, Vibrio alginolyticus and Salmonella typhi. V. cholerae O1 induced, at different cell/bacteria ratios, a significant increase in the percentage of polarized cells compared with PMN cells stimulated with formylmethionyl-leucyl-phenylalanine (FMLP) and the other bacteria tested. The capacity of V. cholerae O1 to induce PMN cell polarization may play a role on the inflammatory response recently described in diarrhoea caused by V. cholerae.