A rapid latex agglutination test, Culturette Brand CDT from Marion Laboratories, was evaluated and compared to a tissue culture assay (TCA) and isolation of Clostridium difficile in 380 faecal specimens from 226 patients with clinically suspected Clostridium difficile-associated diarrhoea. The sensitivity and specificity of the latex test compared with the TCA were 83% and 80% respectively, and the positive and negative predictive values were 55% and 94% respectively. In patients with repeated sampling the sensitivity increased to 95%. The latex test may be useful as a screening test for negative specimens in laboratories where TCA is not available, but positive specimens have to be confirmed by TCA.