Objective: To investigate the effects of enteral nutrition on primary outcomes of patients with severe acute pancreatitis (SAP). Methods: At otal of 253 patients with SAP, admitted between January 1990 and April 2005, receiving the stage nutritional support were divided into two groups, i. e. total parenteral nutrition (TPN) group and parenteral nutrition combined with enteral nutrition (PN + EN) group. While TPN group consisted of 154 patients receiving TPN therapy, PN + EN group consisted of 99 patients receiving PN and EN therapy. The incidence of infections and subsequent complications, the length of hospital stay, and the mortality rates were compared between these two groups. Results: Compared with TPN group, PN + EN group was associated with a lower incidence of pancreatitic infections and hospital mortality rates, but there was no statistically significant difference (10.1% vs. 14.9%; 17.2% vs. 19.5%, respectively; P > 0.05). However, the incidence of infections in other sites and the subsequent complications other than infection in PN + EN group were significantly lower than those in TPN group (20.2% vs. 36.4%, P < 0.05; 40.4% vs. 53.9%, P < 0.05, respectively). Also, the duration of hospital stay was significantly shorter in PN + EN group (31.61 ± 22.85 days vs. 38.17 ± 25.50 days, P < 0. 05). Conclusion: PN combined with EN may be the preferred and rati onal route of nutritional support in patients with SAP.