The association of malignancy with dermatomyositis is well known, and the frequency is reported to be up to 30%. However, cutaneous lymphoma associated with dermatomyositis has rarely been reported. We experienced a case of nasal-type NK/T-cell lymphoma in a 40-year-old woman with a 2-year history of dermatomyositis. To our knowledge, this is the first report of cutaneous involvement of nasal-type NK/T-cell lymphoma developing in a dermatomyositis patient. When skin lesions are resistant to aggressive conventional treatment in dermatomyositis patients, we should consider the possibility of malignancy, especially cutaneous lymphoma.