Two siblings and their mother developed afebrile generalized lymphadenopathy. The lymph nodes were movable and painless. During the course of the illness, the mother and one child developed an uncharacteristic rash. Increased titers of human herpes virus type 6 (HHV-6) antibodies were found in all three family members and in an unrelated patient with lymphadenitis colli. The enlarged lymph nodes decreased in size within several weeks. We speculate these symptoms to be caused by an infection with this lymphotropic virus.