Background: The association of Guillain-Barre syndrome and cerebral sinus thrombosis is uncommon. Case Presentation: We report a 37-year-old patient hospitalized in medical ICU for respiratory distress following a Guillain-Barre syndrome. He had symptomatic treatment in addition to plasma exchange. In the presence of clonic movements, a brain venography magnetic resonance showed a thrombophlebitis of the left lateral sinus, and hence a low-molecular-weight heparin treatment was begun. Immunological, thrombophilia and serological tests were negative. After a favorable evolution, he was transferred to the neurology department. Conclusion: The combination of a Guillain-Barre syndrome and a cerebral sinus thrombosis would suggest a common process. A rigorous investigation, including the use of imaging, is necessary in front of any unusual clinical sign during a GBS.