A segmental pigmentation disorder (SPD) is a form of pigmentary mosaicism. SPD is a hypo- or hyperpigmented patch that has a segmental pattern. A 16-year-old male with an insignificant past medical history presented with symptomless, slowly progressive skin lesions since early childhood. Skin examination revealed well-demarcated, non-scaling, hypopigmented patches on the right upper extremity. A similar spot was located on his right shoulder. Wood's lamp examination showed no enhancement. Differential diagnoses included segmental pigmentation disorder and segmental vitiligo (SV). A skin biopsy was obtained, which revealed normal findings. Based on the above clinicopathological findings, a diagnosis of segmental pigmentation disorder was made. The patient did not receive any treatment but was reassured that he did not have vitiligo.