The term "pigmentation of the oral mucosa" is applied to a wide range of lesions or conditions featuring a change of color of oral tissues. Lesions not associated with an accumulation of pigment (e.g., Fordyce spots) are usually not classified as pigmented lesions. Two groups of pigmented lesions of the oral mucosa are recognized: 1) melanin-associated lesions, including racial pigmentations, melanotic macules, melanocytic nevi, and malignant melanoma; and 2) nonmelanin-associated lesions (e.g., blood-related pigmentations, metallic pigmentations). This paper presents a clinicopathologic review of the recent literature with emphasis on the main diagnostic features, including the use of immunohistochemical markers. A flow-chart is added that may help the clinician in the diagnosis and management of these lesions.