Surgical site infection (SSI) is a potentially morbid and costly complication of surgery. The purpose of this study was to determine preoperative and operative predictors of SSIs after gastric resection with lymphadenectomy in patients with gastric cancer (GC). Data on clinicopathologic factors, including operative and preoperative laboratory factors, for 384 patients with GC who had undergone curative surgery were analyzed in this retrospective study to assess their associations with SSIs. Superficial/deep incisional SSIs (iSSIs) and organ/space SSIs (o/sSSIs) occurred in 18 (4.6%), and 27 (7.0%), respectively. The o/sSSIs were significantly associated with surgery-related factors such as duration of operation, blood loss, and extent of tumor. Additionally, high levels of preoperative indicators of systemic inflammation, including neutrophil counts, neutrophil/ lymphocyte ratio, and C-reactive protein concentrations, were significantly associated with o/sSSIs. Multivariate analyses demonstrated that preoperative neutrophil counts and duration of surgery were independent predictors for o/sSSIs, whereas only preoperative serum albumin concentration was predicted for iSSIs. In patients with GC undergoing curative surgery, preoperative neutrophil count and operation time are potentially valuable predictors of o/sSSIs, whereas only preoperative serum albumin predicts iSSIs.