Lymphomatoid papulosis (LyP), first described by Macaulay in 1968, is a paradoxical skin disease characterized by a generally clinical benign course, in contrast to malignant histological features. LyP is rarely seen in children. We herein report a case of LyP in a 10-year-old boy who had a 4-week history of multiple, scattered erythematous papules, crusted papules or ulcerated papules on the trunk, arms and thighs. Histopathologically, there was a superficial and midderma1 perivascular and interstitia1 infiltrate composed primarily of lymphocytes, which were admixed with large, atypical, mononuclear cells with pleomorphic nucleus. These atypical cells expressed CD30 (Ki-1) antigen. This is the first reported case in Korea of LyP present in a child. (Ann Dermatol 12(3) 225~230, 2000).