Introduction: Nutritional support generates complications that must be detected and treated on time. Objective: To estimate the incidence of some complications of nutritional support in patients admitted to general hospital wards who received nutritional support in six high-complexity institutions. Methods: Prospective, descriptive and multicentric study in patients with nutritional support; the variables studied were medical diagnosis, nutritional condition, nutritional support duration, approach, kind of formula, and eight complications. Results: A total of 277 patients were evaluated; 83% received enteral nutrition and 17% received parenteral nutrition. Some 69.3% presented risk of malnourishment or severe malnourishment at admittance. About 35.4% of those receiving enteral nutrition and 39.6% of the ones who received parenteral nutrition had complications; no significant difference per support was found (p = 0.363). For the enteral nutrition, the most significant complication was the removal of the catheter (14%), followed by diarrhea (8.3%); an association between the duration of the enteral support with diarrhea, constipation and removal of the catheter was found (p < 0.05). For parenteral nutrition, hyperglycemia was the complication of highest inci­dence (22.9%), followed by hypophosphatemia (12.5%); all complications were associated with the duration of the support (p < 0.05). Nutritional support was suspended in 24.2% of the patients. Conclusions: Complications with nutritional support in hospital-ward patients were frequent, with the removal of the catheter and hyperglycemia showing the highest incidence. Duration of the support was the variable that revealed an asso­ciation with complications. Strict application of protocols could decrease the risk for complications and boost nutritional support benefits.