Introduction: Gastric cancer remains an important health problem. Its molecular mechanisms and interactions with the immune system are still not well elucidated. Therefore, we aimed to evaluate the concentration and profile of serum proteins and immunoglobulins in Mexican patients with advanced gastric cancer. Materials and methods: We performed a descriptive study. Adult patients from both sexes were included. The problem group was formed of patients with advanced gastric cancer and the control group was formed of healthy subjects. Demographic data, gastric cancer histological type and stage of tumor node metastasis (TNM) system were recorded. The profile and concentration of serum proteins and immunoglobulins was determined and analyzed in different subgroups classified by sex, histologic type and stage of TNM system. To compare the concentrations of serum proteins and immunoglobulins the ANOVA test was performed. A p <0.05 was considered statistically significant. Results: We included 88 patients with advanced gastric cancer and 74 healthy controls. There were no differences in demographic data among the groups, and the most common gastric cancer type was the diffuse (67.04%). Women with gastric cancer from any type presented higher levels of immunoglobulin G (IgG) compared with the control group (p <0.001) and men with gastric cancer of intestinal type in TNM stage III presented higher levels of IgG compared with its counterpart of diffuse type (p <0.001). Also, patients with intestinal type gastric cancer presented higher concentrations of alpha-1 globulins compared with patients with the diffuse type (p <0.05). Finally, patients with diffuse gastric cancer TNM stage IV presented the lowest albumin/globulin ratios. Conclusion: There is a greater concentration of serum IgG in some subgroups of patients with advanced gastric cancer, the concentration of alpha-1 globulins is different between the intestinal and diffuse types and the albumin/globulin ratio is lower in the diffuse type.