Candida albicans is an opportunistic pathogen that causes significant morbidity and mortality in immunocompromised patients. In this report, the presence of a phospholipase D (PLD) activity in C. albicans, designated CaPLD1, is demonstrated. This is the first description of PLD activity in this organism. CaPLD1 activity was stimulated by inducers of dimorphic transition. Furthermore, transition was stimulated by the addition of exogenous PLD to cells. The addition of 1-propanol to the medium, which resulted in the production of phosphatidylpropanol by CaPLD1 at the expense of the usual product phosphatidic acid, delayed the yeast to hypha transition. These results suggest that CaPLD1 may be an important regulator of dimorphic transition in C. albicans.