Objectives: The aim of the study was to investigate the effect of copper-bearing intrauterine device (IUD) use on the virulence of Candida species causing vulvovaginal candidiasis (VVC). The in vitro ability of Candida species to produce proteinase and phospholipase enzymes was studied, together with their antifungal susceptibility.Methods: Vaginal swabs from women with VVC were cultured and Candida species were identified. Participants comprised 132 women with culture-confirmed VVC, of whom 65 were using a copper-bearing IUD and 67 were not. Candida isolates were tested for their ability to produce proteinase and phospholipase as well as for their susceptibility to fluconazole and nystatin.Results: Proteinase production was higher in non-albicans Candida (NAC) isolates of IUD users compared with non-users (p = 0.017). IUD use was significantly associated with antifungal resistance of NAC isolates to fluconazole (p = 0.013) and nystatin (p = 0.018). By contrast, IUD use seemed to significantly reduce the production of proteinase by C. albicans (p = 0.041), with no effect on its antifungal susceptibility. There was a significant negative correlation between proteinase production in both C. albicans and NAC as well as sensitivity to fluconazole (r= -0.383, p < 0.05 and r= -0.497, p < 0.05, respectively).Conclusion: IUD use enhanced the virulence (proteinase production and antifungal resistance) of NAC but not C. albicans, indicating a variation in virulence between Candida species in response to IUD use. C. albicans responded better to fluconazole, whereas NAC isolates were more sensitive to nystatin.