Levamisole has been used to treat a patient with disseminated neonatal herpes simplex infection. The skin lesions and the convulsions disappeared completely 20 days after therapy. A trial to reduce the dose of levamisole resulted in a new episode of seizures and skin lesions. A similar relapse was observed at the age of 7 months, which resulted in control of symptoms by increasing the dose of levamisole. The patient has received levamisole for 20 months. She is now 29 months old and is doing well without levamisole, except for a slight motor deficit. If further investigations confirm the present findings, levamisole may well become a useful agent in the treatment of disseminated herpes simplex infection.