While most dermal melanocytoses are congenital or have an onset in early childhood, there is an acquired group with a late onset. We describe a case of aldolescent onset, unilateral, macular dermal melanocytosis on the hand. A 16-year-old girl presented with a 10-month history of gray-bluish pigmentation on the right palm and the volar side of the right fourth finger. The light microscopic studies showed spindle-shaped dermal melanocytes. The S-100 protein staining of these cells was positive and CD68 staining was negative. Dermal melanocytosis of the macular type, as observed in our case, is very rare.