Longitudinal pigmentation of the nail is very common. The differential diagnosis varies from subungual hematoma, to a fungal infection, to a melanocytic lesion (lentigo, nevus melanoma, etc.) to others. Often, dermatologists do not feel at ease with these pathologies and management is often not clear. In many cases, a biopsy is not helpful because an inadequate technique was chosen. The use of noninvasive techniques such as dermoscopy has been described to be useful for the preoperative evaluation and the management decision. Using these technique, one will be able to reduce the number of unnecessary surgeries and to choose the most adequate biopsy technique. In this article, we will review the management, including diagnosis as well as differential diagnosis of nail pigmentations and propose a new algorithm for the non invasive diagnosis of nail pigmentation.