Background: Obesity is generally considered to be associated with increased postoperative morbidity and mortality following intraabdominal cancer surgery. However, recent reports showed that overweight patients may have a lower risk for adverse postoperative outcomes and this observation has been described as the ‘obesity paradox'. Therefore, we aimed to analyze the impact of obesity on outcomes after resection for gastric cancer. Methods: Data of patients who underwent resection for gastric cancer between 2005 and 2012 were assessed. Patient characteristics, postoperative outcomes and long-term survivals were compared between patients with body mass index (BMI) ≥30 and <30. Results: Resection for gastric cancer was performed in 249 patients. BMI ≥30 was identified in 49 patients. Obese patients with BMI ≥30 were more frequently diagnosed with diabetes (31 vs. 16%, p = 0.015). Resection for gastric cancer in obese patients was significantly associated with longer duration of surgery (278 vs. 243 min, p < 0.001), longer duration of hospital stay (18 vs. 16 days, p = 0.028), increased postoperative morbidity (49 vs. 33%, p = 0.037), and increased postoperative mortality (10 vs. 3%, p = 0.028). There was no significant difference in overall survival (OS) between patients with BMI ≥30 and patients with BMI <30 (5-year OS rate: 59 vs. 62%, p = 0.587). Conclusion: Obesity may complicate resection for gastric cancer increasing the duration of surgical procedure, hospital stay and postoperative morbidity and mortality. However, BMI did not predict OS in our patients. Consequently, BMI may be too simple as a parameter to evaluate sophisticated interactions between different body fat compartments and inflammatory and immune responses and thus to predict long-term oncologic outcomes.