We report a case of primary cutaneous mucinous adenocarcinotna in a 64-year-old female. The tumor was about 2cm in size, forminga round dome-shaped alopecic scalp mass which had gradually increased in size over about 5 years, Histalogic examination revealed that the tumor was divided into numerous compartments by strands of fibrous tissue. In each compartment, abundant amounts of pale-staining mucin surrounded nests or cords of moderately anaplastic epithelial cells. We couldn't find any evidence of internal neoplasms as a source of metastasis. We resected the tumor with approximately a 1 cm margin and then performed a split thickness skin graft. (Korean J Dermatol 1999;37(4) : 523-527)