Background: Candidiasis is a spectrum of opportunistic fungal diseases that can manifest in drug addicts in various forms, such as stomatitis. Objectives: This study aimed to determine the prevalence of oral candidiasis caused by Candida glabrata in addicts and examine the susceptibility of isolates to two azoles. Patients and Methods: After taking oral samples from 131 drug addicts suspected of having oral candidiasis, Candida species were identified by culture on chromogenic Candida agar, carbohydrate-assimilation (API test), and polymerase chain reaction. The minimum inhibitory concentrations (MICs) of fluconazole and voriconazole against the isolates were determined using the broth microdilution method. Data were analyzed by SPSS (version 23) using the t-test and one-way analysis of variance. A P value of less than 0.05 was considered statistically significant. Results: Overall, 22.2% of the isolates were C. glabrata, which was more abundant among opiate addicts. Among these isolates, 61.1% were resistant to fluconazole and 44.4% were resistant to voriconazole. The MIC90 of voriconazole was 8 µg/mL, which was 16 times less than that of fluconazole (128 µg/mL). There was no statistically significant difference between the frequency of fluconazole-and voriconazole-resistant isolates (P > 0.05). Conclusions: Oral candidiasis was a common problem among drug addicts. In addition, the prevalence of azole-resistant C. glabrata isolates was high among these individuals.