CaNdt80p, the Candida albicans homologue of the Saccharomyces cerevisiae transcription factor ScNdt80p, has been identified as a positive regulator of CDR1, which encodes an efflux pump involved in drug resistance in C. albicans. To investigate the involvement of the putative DNA-binding domain of CaNdt80p in drug resistance, chimeras of CaNdt80p and ScNdt80p were constructed. Interestingly, the DNA-binding domain of ScNdt80p could functionally complement that of CaNdt80p to activate CDR1p-lacZ in S. cerevisiae. Consistently, CaNdt80p containing a mutation in the DNA-binding domain failed to activate CDR1p-lacZ in S. cerevisiae. Furthermore, a copy of CaNDT80 with the same mutation also failed to complement the drug-sensitive phenotype caused by a null mutation in C. albicans. Thus, the DNA-binding domain of CaNdt80p is critical for its function in drug resistance in C. albicans.