Objective To investigate the correlation between vitamin C levels nutritional indicators and inflammatory parameters in gastric cancer patients. Method 156 cases of gastric cancer patients were selected from those admitted to the First Affiliated Hospital of Guangxi Medical University between July and December 2023. Nutritional risk screening 2002 NRS 2002 and patient-generated subjective global assessment PG-SGA were used to evaluate the nutritional risk and nutritional status within 24 hours of admission. Meanwhile serum vitamin C levels and inflammatory markers were measured and the inflammatory-related indices were calculated. Single-factor analysis and multiple-variable Logistic regression analysis were performed to analyze the indicators for different vitamin C groups. Result Among the 156 gastric cancer patients 60. 26% 94 / 156 exhibited vitamin C deficiency. Among the 46. 79% 73 / 156 patients with nutritional risk 73. 97% 54 / 73 had vitamin C deficiency. According to the PG-SGA results moderate or severe malnutrition was identified in 68. 59% 107 / 156 of the patients with 70. 09% 75 / 107 exhibiting vitamin C deficiency and 82. 46% 47 / 57 of patients with severe malnutrition had vitamin C deficiency. Among the patients with high vitamin C albumin ALB prealbumin PA lymphocyte -to -monocyte ratio LMR prognostic nutritional index PNI and C- reactive protein - albumin - lymphocyte index CALLY were significantly higher than the patients with low vitamin C while NRS 2002 score PG-SGA score interleukin-6 IL-6 C-reactive protein CRP neutrophil to lymphocyte ratio NLR and systemic immune-inflammatory index SII were significantly lower than the patients with low vitamin C P< 0. 05 . Logistic regression analysis revealed that PG-SGA score IL-6 and CRP were independent risk factors for vitamin C deficiency P<0. 05 . Conclusion The proportion of gastric cancer patients with insufficient vitamin C is relatively high and patients with nutritional risk or malnutrition are more prone to vitamin C deficiency. Gastric cancer patients should regularly monitor vitamin C levels.