Adenovirus infections are very common diseases, especially upper respiratory infections and diarrhea in infants. Moreover, adenoviruses can occasionally produce CNS infections. The common causative adenovirus is type 7 for them, and they have been associated with pneumonia and epidemics of adenovirus in family outbreaks. Reye-like syndrome has rarely been reported. As AIDS and other immunocompromised patients have increased, new reports of adenovirus CNS infections have also increased. Of course the immunosuppressed conditions have included lymphoma, transplant etc. In the near future, long term care for immunocompromised patients will have a crisis of adenovirus CNS infection. On the other hand, adenovirus CNS infections are difficult to diagnose precisely without special facilities, due to the need for adenovirus cultivation from CSF. In addition, the diagnosis may have limitations due to the many subtypes of adenovirus. Despite the benefits of PCR methods, standard laboratory testing procedures are still not established for diagnosis.