Aim: To analyze the insulin-like growth factor 1 (IGF-1) serum levels in nonagenarian patients and to investigate the predictive capacity of this measure to assess the functional recovery of this population following hospitalization. Methods: We performed a prospective study in 60 consecutive nonagenarian patients admitted for medical or surgical diseases. We assessed IGF-1 serum levels and nutritional status. The functional status was assessed using the Barthel index. Thirty-four patients were reinvestigated 3 months after discharge from hospital. Results: The mean levels of IGF-1 were lower in nonagenarians than in younger patients. No relationship was found between IGF-1 levels and nutritional status. The decline in Barthel index values 3 months after discharge from hospital did not correlate with serum levels of IGF-1 on admission. Conclusion: IGF-1 serum levels in nonagenarian patients do not predict functional recovery after hospitalization.