A case of oral melanoacanthoma was presented. The differential diagnosis of pigmented lesions of the oral mucous membrane includes a wide variety of categories of disease including local and systemic manifestations of hereditary and developmental conditions, reactive and inflammatory lesions, neoplasms, and metabolic diseases. For some of these lesions the histopathological pattern is diagnostic; for others, the tissue structure and organization are nonspecific and intelligent evaluation requires clinicopathological correlation. This discussion of oral mucosal pigmented lesions emphasizes the importance of the clinical parameters in the differential diagnosis of this group of lesions.