Progressive multifocal leukoencephalopathy (PML) is a demyelinating neurologic disorder caused by a polyomavirus, called JC virus. PML affects mainly immunocompromised hosts. We report a case of PML as first manifestation of sarcoidosis in a previously healthy man. Treatment with cidofovir, resulted in a neurological and radiological stabilization. To our knowledge the association of PML and sarcoidosis without previous immunosuppressive treatment has only been described in a few cases, none of them were treated with cidofovir.