A 61-year-old man with an antecedent febrile illness presented with progressive flaccid paraparesis, but no sensory or sphincter involvement. Magnetic resonance imaging (MRI) of the spine was negative and nerve conduction study (NCS) showed the absence of F-waves in his legs, suggesting Guillain-Barré syndrome (GBS). However, abdominal pain after admission led to the consideration of the spinal cord ischemia secondary to aortic dissection confirmed by computed tomography. We report the rare condition of painless aortic dissection simulating GBS.