Introduction: Patients with type 2 diabetes mellitus are susceptible to acquire Candida spp. infections, sometimes involving more than one species. The resistance of some species to antimycotic agents can cause treatment failure., Objectives: To determine the frequency and clinical varieties of mixed oral candidiasis in patients with type 2 diabetes mellitus, the involved species, and its sensitivity spectra when exposed to antifungals used as candidiasis treatment., Material and Methods: We developed an analytical cross-sectional study with 72 patients with type 2 diabetes mellitus with hyperglycemia (HbA1C ≥ 7%) and an oral candidiasis diagnosis. The causal species of oral candidiasis were identified through microbiological techniques, and sensitivity tests were carried out using the diffusion method in a plate with strips (E-test ®)., Results: We included 72 patients in the study, 32 (44%) males and 40 (56%) females. Patients were divided into three age groups: young adults (17%), adults (74%), and older adults (9%). The mean age of the patients was 51 years. No significant differences were found between mixed oral candidiasis and groups (sex and age), or between mixed oral candidiasis and gender, glycosylated hemoglobin level (HbA1C), antihyperglycemic treatment, or type 2 diabetes mellitus time of diagnosis. We found a correlation between the adult group and development of mixed or simple oral candidiasis. The results showed eight (13%) cases of mixed oral candidiasis: seven with a coinfection of two species and one with a coinfection of three species. The identified species were Candida albicans, C. glabrata, C. dubliniensis, C. kefyr, C. tropicalis, and C. krusei. Most of these species presented sensitivity against ketoconazole and fluconazole, and higher resistance to itraconazole., Conclusions: Mixed oral candidiasis occurs in approximately 10% of the patients with type 2 diabetes mellitus and its treatment can be ineffective when the etiological agent is not identified.