PURPOSE: Protein and energy malnutrition are common in patients with stomach cancer. Nutritional assessment is very important because malnutrition has been shown to be associated with increased morbidity and mortality in stomach cancer. Therefore, this study analyzed the relationship between the nutritional status and the number of hospitalization days in stomach cancer patients. METHODS: The study subjects were 89 patients with stomach cancer, who were admitted to the General Surgery Department during August 2001 to December 2001. The initial nutrition status was assessed using biochemical, anthropometric, and subjective global assessment (SGA) data along with the number of hospitalization days. RESULTS: The study was showed that the mean age was 55.9, the gender ratio was 1.3 : 1 and the mean hospitalization days were 15.59 and there was no statistically significant difference. The weight changes during 1 month before surgery, weight change during 6 month before surgery, usual body weight, and serum albumin level were associated with the nutritional status. The Pearson's correlation test revealed statistically significant relationships between the number of hospitalization days and the MAC (mid-arm circumference), MAMC (mid arm muscle circumference), and serum albumin level. Moreover, according the logistic regression test, MAMC was most associated with the number of hospitalization days. According to stomach cancer stage, only the serum triglyceride level was showed a statistically significant association. However, the Pearson's correlation test revealed the MAC and serum albumin level to be associated with the number of hospitalization days. CONCLUSION: A nutritional assessment should be carried out in cancer patients pre-operatively. Moreover, the number of hospitalization days after surgery should decrease with adequate nutritional support. These results show that MAMC is most adequate data for assessing the nutritional status and could play a key role in decreasing the number of hospitalization days after surgery with adequate nutritional support. In addition, monitoring of the laboratory levels, such as albumin, triglyceride, and transferring, could be helpful in decreasing the number of hospitalization days. However, the other laboratory parameters, such as cholesterol, zinc, and total lymphocyte count, were not associated with the number of hospitalization days.