Condyloma lata is a common manifestation of secondary syphilis, but involvement of the lip mucosa is rare. Nodular lesions, especially solitary nodules, are uncommon manifestations of secondary syphilis, and only a few cases have been described. Failure to recognize condyloma lata of the lip mucosa may delay diagnosis and treatment. A 20-year-old man presented with a 4-month history of a solitary nodule on his upper lip mucosa. A diagnosis of condyloma lata was made on the basis of serologic tests for syphilis and pathological findings. We report an interesting case of condyloma lata on the upper lip mucosa that showed an unusual clinical manifestation of secondary syphilis. (Korean J Dermatol 2008;46(12):1648∼1650)