Sarcoidosis is a multi-system, non-caseating granulomatous disease of unknown etiology. Although spinal cord involvement is rare, it may cause severe neurological complications. We report the case of a 52-year-old woman who developed low back pain and a progressive flaccid paraparesis whose investigations revealed pulmonary and spinal sarcoidosis. To our knowledge, this is the first reported case of sarcoidosis of the conus medullaris and cauda equina diagnosed by an unusual enhancement pattern observed on magnetic resonance imaging with gadolinium. Biopsy of the lumbar nerve roots and of the lung revealed a non-caseating granuloma. Treatment with steroids and intensive rehabilitation resulted in remarkable functional improvement. Although rare, sarcoidosis of the conus medullaris and cauda equina should be considered in the differential diagnosis of flaccid paraparesis, particularly in patients with non-diagnostic evaluations.