Multiple sclerosis (MS) is the prototypical inflammatory disease of the central nervous system and spinal cord, leading to axonal demyelination of neurons. Recently, we have found a correlation between fungal infection and MS in peripheral blood of patients. The present work provides evidence of fungal infection in the cerebrospinal fluid (CSF) of some MS patients. Thus, fungal antigens can be demonstrated in CSF, as well as antibodies reacting against several Candida species. Comparison was made between CSF and blood serum for the presence of fungal antigens (proteins) and antibodies against different Candida spp. Analyses of both CSF and serum are complementary and serve to better evaluate for the presence of disseminated fungal infection. In addition, PCR analyses indicate the presence of DNA from different fungal species in CSF, depending on the patient analyzed. Overall, these findings support the notion that fungal infection can be demonstrated in CSF from some MS patients. This may constitute a risk factor in this disease and could also help in understanding the pathogenesis of MS.