Background and Objective: Vulvovaginal Candidiasis is one of the most common vaginal infections which can be related to the use of IUD. Determination of candida species which lead to vulvovaginal candidiasis is very important for proper treatment. This study aims to assess the effect of IUD insertion on Candida fungal flora in cervicovaginal smears. Materials and Methods: This prospective longitudinal study was performed in health centers affiliated to Tehran University of medical sciences from Nov. 2011 through Sep. 2012. 95subjects who had selected Copper T-380-A IUDs as a contraception and had no history of local or systemic antibiotics or antifungals use during the last 2 weeks, were considered eligible candidates. After obtaining the clients’ written consent, cervicovaginal swab specimens were collected and cultured on Sabouraud Dextrose Agar, before and 3 months after IUD insertion. Produced white colonies were cultured on Chrom Agar Candida. Then, species were differentiated by different colors. The SPSS 16 was used to analyze the collected data. P-value <0.05 was considered significant. Results: The occurrence of candidiasis was significantly increased 3 months after IUD insertion (25% vs 11.6%, P= 0.007). The most common identified species before and after IUD insertion was c.albicans and then c.glabrata. Conclusion: Because of the increase in the prevalence of candidiasis after IUD insertion, further investigations with larger samples and variety of settings are needed to evaluate the exact health risks or benefits of IUDs. Increase in the prevalence of candida glabrata as one of the resistant species to azole drugs is of importance.