Purpose: To examine the effects of age on differences in the clinical course and functional outcome of mechanically ventilated Guillain-Barré syndrome (GBS) patients. Methods: 32 consecutive patients with GBS in need of mechanical ventilation were divided into two groups: (1) 15 patients <65 years, and (2) 17 patients ≥65 years. Length of ventilation, therapy, incidence of bulbar involvement, dysautonomia, preceding infections, need for tracheostomy, mortality, and functional outcome at 1-year follow-up using the Hughes outcome scale were analyzed. Results: The groups were comparable regarding treatment, lesion type, incidence of bulbar involvement, dysautonomia, preceding infections and duration of ventilation. The majority of patients (75%) received combination therapy (intravenous immunoglobulin and plasma exchange). Tracheostomy was performed in 91% of patients. Mortality was higher in older patients (41 vs. 7%; p = 0.02) and overall outcome worse (p = 0.05). Interestingly, once surviving the early, most critical period, older patients functionally recovered as well as younger patients (80% good outcome vs. 86%; p = 0.71). Conclusions: Despite all the advances in intensive care, mortality in older, ventilated GBS patients is still substantial. However, once they have survived the early, most critical period, older patients may recover as well as younger patients. Special care should therefore be taken to prevent and, if present, to vigorously treat complications commonly associated with intensive care treatment of severe GBS in elderly patients.