Objective: The aim of the study is to investigate the evolution of nutritional parameters after major spinal surgery in patients with idiopathic scoliosis. Methods: This retrospective study included 31 patients with a mean age of 18 y, diagnosed with idiopathic scoliosis. The following variables were analyzed: demographic, surgical (type, number of fused segments, duration, and blood loss), nutritional assessment (proteins, albumin, prealbumin, transferrin, lymphocytes, and body mass index), and duration of hospitalization at different time points. Statistical analyses were performed with the SPSS 6.1 software. Results: Before surgery, nutritional status was normal in all patients. At 24-48 h after surgery, statistically significant decrease with respect to preoperative values was recorded for all the parameters studied: proteins (Po0.001), albumin (Po0.001), prealbumin (Po0.01), transferrin (Po0.001), and lymphocytes (Po0.001). Conclusion: Our results showed a significant postoperative decrease in the nutritional parameters analyzed in a previously wellnourished population considered to be at low risk for nutritional depletion.