A coagglutination procedure for detecting Vibrio cholerae was applied directly to 125 watery fecal samples received in the laboratory for bacteriological culture: many of these were from suspected cases of cholera. Of 47 bacteriologically proved cases of cholera, 44 (93.6%) gave positive results by the coagglutination method. There was a good correlation between the coagglutination method, dark-field microscopy, and culture.