The phrase "pigmentation of oral mucosa" is used to describe a wide variety of diseases or disorders that cause a change in the colour of oral tissues. Petechiae, purpura, ecchymoses, hematomas, vascular tumours, and foreign substances are frequent sources of mucosal colouring but are not genuine pigmented lesions. As a real pigment, melanin, which is produced by melanocytes, gives the mucosa its characteristic colour of brown, blue, or black. The doctor may face a diagnostic conundrum if pigmented tissue is seen in the mouth cavity. The appearance of mucosal pigment varies and might take the form of a tiny nodule to a big mass or a focused to widespread macular colour. There is a physiological basis for pigmentation, it may indicate a cancerous process. Oral pigmentation requires a thorough examination of patient to rule out any malignancy associated with it. The present article reviews the oral pigmentations in detail, which will serve as a ready reference for the dentists.