A human fungal pathogen, Candida albicans, varies from the yeast form to the hyphal form due to various external signals. This morphogenetic transformation has been implicated in the development of pathogenicity. In this report, we show that calmodulin inhibitors (TFP and W-7) and an adenylatecyclase inhibitor (MDL-12-330A) suppressed the hyphae formation of C. albicans. Furthermore, the expression of hyphae-specific mRNAs located downstream from the RAS1-cAMP pathway was inhibited by these inhibitors. Suppression of hyphae formation by TFP or W-7 was not inhibited by the addition of cAMP, and these inhibitors did not affect the amount of cAMP in C. albicans. These results suggest that the Ca²⁺/calmodulin pathway contributes to hyphae formation and is related to the RAS1-cAMP pathway.