It is anticipated that the number of elderly patients with gastric cancer (GC) will increase with population aging; however, most studies on GC set the upper age limit at 80 years old, studies on the prognosis of elderly patients with GC over 80 years old is very limited. In this study, we conducted a retrospective analysis of this sub-cohort. This retrospective cohort study aimed to analyze the clinical data of patients aged >80 who died of GC in People's Liberation Army General Hospital between 1985 and 2020. We collected clinical informations about pathological GC types, differentiation degrees, clinical stages, anatomic sites and Bormann types of the selected case. Characteristics of participants, such as smoking, drinking, and tumor history, age, gender, and complications, were also recorded. The Kaplan-Meier method, a multivariate Cox multivariate proportional hazard model, and logistic regression were used to analyze the patient overall survival (OS) rates and treatment outcomes. The study included 92 patients (83.7% men) with a median OS of 45 months. The most common site for GC was the gastric antrum (GA), the most common site of metastatic spread was the liver, and the most common pathological GC type was tubular adenocarcinoma/papillary adenocarcinoma (TAC/PAC). Furthermore, the prevalent complications were hypertension, coronary heart disease, and diabetes. Diabetes was a risk factor affecting the total survival time [hazard ratio (HR) =2.326, P=0.029]. The most often-used GC treatment was curative surgery. The survival time was significantly longer in the curative surgery group and curative surgery + adjuvant chemotherapy group compared with the support care group (HR =0.119, P=0.001; HR =0.110, P=0.001). There was no significant difference in survival time among the palliative chemotherapy group, palliative surgery group, and support care group. Tumor staging was significantly correlated with OS rate, the median survival time of patients at stage III and stage IV GC were significantly lower than the median survival time of patients at stage I GC (HR =6.235, P=0.001; HR =30.955, P=0.001). For patients over 80 years old with good physical conditions in the early stage of GC, more active treatment can still bring better prognosis.