The aim of this graduate thesis isto study pigmentations of the oral mucosa througha review ofliterature and a case report. Pigmentations of the oral mucosa are very common finding lesions in the oral cavity. Discolorations can appear as a result from many causes, causes that can be exogenus and endogenus in origin. Pigmentations can represent physiologic changes, some systemic disordes, hormonal disorders or even malignant change. Also, pigmentations can represent in a large spectrum of colors. Oral pigmentations can be solitary, multifocal or diffuse and can reflect on any side of the oral mucosa. Diagnose of a patient with this kind of lesion includes full medical history, family history, informations about duration and simptoms of lesion. Also, extraoral and intraoral review must be given in a combination with radiographic investigations, sometimes biopsy and laboratory investigations. This graduate thesis also reports a case of oral pigmented lesions associated with smoking in a young female patient.