Primary CD30 negative large T cell lymphomas consist of CD30 negative large tumor cells without prior or concurrent mycosis fungoides. Clinically, it presents with solitary, localized or generalized plaques, nodules, or tumors and most cases show an aggressive clinical course. The histologic apperance may be identical to that of classic mycosis fungoides undergoing transformation into large cell lymphoma and large tumor cells represent at least 30 percent of the total tumor cell population. We experienced a case of CD30 negative large T cell lymphoma and report it with a review of literatures.(Korean J Dermaton 2003;41(10) : 1402~1405)