A 54-year-old man had intermittent evening fever, arthralgia, transient erythematous macular eruption on the skin, and splenomegaly of two year's duration. Immunofluorescence tests for Borrelia burgdorferi serum antibodies had positive results, but G-penicillin treatment was ineffective. Splenectomy with lymph node biopsy was performed to rule out lymphoproliferative disorders. Borrelia-like spirochetes were identified histologically in the spleen; this finding was consistent with persistence of B. burgdorferi organisms in inner organs in chronic Lyme disease.