Cutaneous mesenchymal hamartoma (CMH) is a very rare disease which most often presents itself at birth and is composed of collagen fibers, immature fibroblasts, fat cells, blood vessels, and mast cells. Until recently, only two cases have been reported. Thus, the clinical and histopathological findings have been unsettled. We describe three cases of cutaneous mesenchymal hamartoma with different clinical findings, discuss its pathogenesis, and suggest that CMH is a distinct disease entity. (Ann Dermatol 10(4) 262-265, 1998).