Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 11 5 2019 11 12 357 362 Sara Haghighat Department of Oral and Maxillofacial Medicine, Student Research Committee, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran Fahimeh Rezazadeh Department of Oral and Maxillofacial Medicine, Oral and Dental Diseases Research Center, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran 2018 10 30 2019 08 04 Background and Objectives: Oral mucosal infections are an important type of oral lesions. The aim of this study was to determine the epidemiology of oral mucosal infectious lesions in patients who referred to Oral Medicine Department of Shiraz Dental School, Iran during 11 years. Materials and Methods: In this cross sectional study, records of all patients who referred to Oral Medicine Department of Shiraz Dental School from September 2007 to January 2018 were assessed and those data sheets which their definitive diagnosis were a kind of oral mucosal infectious lesion were recorded. Pearson Chi- square test was used for statistical analysis. Level of significance was considered as P value < 0.05. Results: Overall prevalence of oral mucosal infectious lesions was 9.47%. Generally, mean age of patients was 42.92 ± 18.84 and most of them were female. Most common type of infectious lesions was fungal infections, but viral and bacterial infections were less common. Among fungal infections, most lesions were candidiasis and only 3 cases were diagnosed as deep fungal infection. HSV infection was the second common oral infectious lesion. There was a significant relation between infectious lesion and systemic disease or medication use (P=0.000). Conclusion: This study is the first epidemiologic study in Iran, concerning oral mucosal infectious lesions. Total of 9.47% of oral lesions were infective, candidiasis and HSV lesions were the most common oral mucosal infective disease, which were more prevalent amongst female, middle age people and patients with systemic disease. https://ijm.tums.ac.ir/index.php/ijm/article/view/1941 https://ijm.tums.ac.ir/index.php/ijm/article/download/1941/1189