Agminated blue nevus (ABN) is a melanocytic nevus rarely mentioned in the literature and not well known. The term agminated is used when many blue nevi are clustered together in a sharply demarcated area ≤10 cm. Specific dermatoscopic features have not currently been clearly defined. We describe two cases of ABN and provide a review of the literature, reporting the main points in order to facilitate the diagnosis of this rare entity.