Seven isolates each of Candida albicans and Candida dubliniensis were paired (11 pairs) and examined for competitive interaction. Equal numbers of CFU of each competitor were inoculated into Sabouraud dextrose broth and incubated at 37 degrees C with vigorous shaking under conditions favorable to either broth or biofilm growth. Surviving proportions of each competitor were calculated from the broth culture at 24 and 96 h and the biofilm culture at 96 h, with species differentiation done on CHROMagar Candida medium. C. albicans had a competitive advantage over C. dubliniensis in broth culture and under biofilm growing conditions; however, with the presence of a supporting structure for biofilm formation, C. dubliniensis was able to better withstand the competitive pressures from C. albicans.