Ankylosing spondylitis is a very uncommon finding in patients with sarcoidosis. Thirteen cases have been reported in the literature. We report a new case. Observation. - A 40-year-old man had inflammatory low back pain since 1983 which formerly responded to nonsteroidal inflammatory drugs (NSAIDs). He developed dyspnea and skin rash in 1993. Physical exam found cervical and lumbar spine stiffness and violaceous and circular lesions on the forehead, nose and right cheek. Laboratory tests showed: ESR at 50 mm, increased serum angiotensin-1-converting enzyme, and negative HLA B27. X-rays showed sacroiliac ankylosis, cervical and lumbar syndesmophytes and cervical facet joint ankylosis. The plain chest x-ray showed an interstitial syndrome. Chest CT scan showed mediastinal adenopathies. Skin biopsy disclosed non-caseating epitheliod and giant-cell granuloma. Outcome was good with steroid therapy but back pain was only improved by NSAIDs. - This association raises a diagnostical problem because spine involvement in sarcoidosis can mimic ankylosing spondylitis. It also suggests the hypothesis of a pathophysiological link between the two diseases.