Purpose: Considering that nutritional state correlates to immunity, we performed this study to evaluate the correlation by assessing the numerical changes of the levels of serum albumin and lymphocyte subsets. Materials and Methods: The study was performed on patients who were diagnosed as having gastric cancer and who underwent curative surgery from August 1998 to August 2004 in the Gyeongsang National University Hospital and whose peripheral blood lymphocyte subsets were tested prior to surgery. The study population was a total of 150 cases. Results: The change in the lymphocyte subsets in relation to the change in the level of serum albumin in all patients with gastric cancer was determined, and was compared to disease stages. When patients were classified by using the level of serum albumin with 3.2 mg/dl as the cut-off point (low group: serum albumin <3.2 mg/dl, normal group = serum albumin $geq$ 3.2 mg/dl), the number of peripheral blood lymphocytes, CD3+ cells, CD4+ cells, CD8+ cells, and CD16+ 56 cells were, significantly lower in the group with the level of serum albumin below 3.2 mg/dl (low group) than it was in the group with a serum albumin level above 3.2 mg/dl (normal group) (P<0.05). In stage I (n=59), CD16+56 cells were significantly lower in the low group. In stage II (n=29), the number of CD16+56 cells was lower and the ratio of CD4+/CD8+ was higher in the low group than in the normal group significantly. In stage IV (n=33), except for CD19+ cells, the number of all lymphocyte subsets was significantly lower and the ratio of CD4+/CD8+ was significantly higher in the low group. Conclusion: The group with a low level of serum albumin had a low absolute number of lymphocyte subsets. Based on this, we reconfirmed that the nutritional state is closely related with the immune state in patients with gastric cancer.