This study aimed to evaluate the prevalence and factors associated with oral mucosa alterations in patients from Vale do Jequiti-nhonha, Brazil. The sample consisted of 511 patients of both genders. Questionnaires were used to obtain information about patient gender, age, race, systemic disease state, medication use, cigarette use and alcohol consumption. Physical examinations were then performed to identify lesions of the oral mucosa. Descriptive analyses, Chi-squared tests and logistic regressions were then used to analyze the results (p < 0.05, 95% CI). In this population, 84.9% (434/511) of patients were found to have alterations in their oral mucosa. The most common alterations were melanotic maculae (36.0%), linea alba (33.9%), traumatic ulcers (21.5%), Fordyce's granules (20.4%), coated tongue (12.5%) and fissured tongue (10.0%). Melanotic maculae were more frequently observed in black patients, with an odds ration (OR) of 7.51. Being female was a statistically significant predictive factor for having a visible linea alba (OR: 1.90) and a fissured tongue (OR: 2.11). No statistically significant association was found between the presence of oral lesions and systemic disease, medication use, alcohol use and smoking. The high observed prevalence of melanotic maculae and Fordyce's granules suggests that these alterations could be considered typical characteristics of the population of the Vale do Jequitinhonha. Coated tongue may be related to the socioeconomic deprivation in the region. Furthermore, the high prevalence of traumatic ulcers may be associated with the traumatic agents that caused patients to seek dental care.