In the present work the sensitivity of yeast strains of Kluyveromyces marxianus, Pichia anomala, Candida utilis, Schizosaccharomyces pombe and Saccharomyces cerevisiae, to the fungicides cymoxanil, penconazol, and dichlo¯ua-nid, was evaluated. Dichlo¯uanid induced the most negative eects, whereas penconazol in general was not very toxic. Overall, our results show that the parameters IC 50 for speci®c respiration rates of C. utilis and S. cerevisiae and C D for cell viability of S. cerevisiae can be applied to quantify the toxicity level of the above compounds in yeast. Hence, could be explored as an alternative or at least as a complementary test in toxicity studies and, therefore, its potential for inclusion in a tier testing toxicity test battery merits further research. Ó