To assess the association between nutrition status and prognosis of patients with digestive system cancer, epidemiological investigations were conducted in 2 periods to obtain information about the patients' nutrition status, survival time, and quality of life. Relative risks and 95% confidence intervals were estimated by logistic regression. Among the patients with esophagus, stomach, and colorectal cancers, nutritional indicators at time 1 did not affect relative risk for survival at time 2. At time 2, relations between quality of life and albumin, daily intake of calories, and daily intake of protein were statistically significant (P < .05). This study offers evidence that nutrition status shortly after operation does not affect 1-year survival rate and that nutritional status at 1 year is associated with quality of life.