BackgroundThe serum systemic inflammation biomarkers have been established as predictors of prognosis in gastric cancer (GC) patients, but their prognostic value in human immunodeficiency virus (HIV)-infected patients with GC has not been well studied. This retrospective study aimed to evaluate the prognostic value of preoperative systemic inflammation biomarkers in Asian HIV-infected patients with GC.MethodsWe retrospectively analyzed 41 HIV-infected GC patients who underwent surgery between January 2015 and December 2021 at the Shanghai Public Health Clinical Center. Preoperative systemic inflammation biomarkers were measured and patients were divided into two groups based on the optimal cut-off value. Overall survival (OS) and progression-free survival (PFS) were measured using the Kaplan–Meier method and the log-rank test. Multivariate analysis of variables was performed using the Cox proportional regression model. As a comparison, 127 GC patients without HIV infection were also recruited.ResultsThe median age of the 41 patients included in the study was 59 years, with 39 males and two females. The follow-up period for OS and PFS ranged from 3 to 94 months. The cumulative three-year OS rate was 46.0%, and the cumulative three-year PFS rate was 44%. HIV-infected GC patients had worse clinical outcomes compared to the normal GC population. The optimal cut-off value for preoperative platelet to lymphocyte ratio (PLR) was 199 in HIV-infected GC patients. Multivariate Cox regression analysis revealed that a low PLR was an independent predictor of better OS and PFS (OS: HR = 0.038, 95% CI: 0.006–0.258,P< 0.001; PFS: HR = 0.027, 95% CI: 0.004–0.201,P< 0.001). Furthermore, higher preoperative PLR in HIV-infected GC was significantly associated with lower BMI, hemoglobin, albumin, CD4 + T, CD8 + T, and CD3 + T cell counts.ConclusionThe preoperative PLR is an easily measurable immune biomarker that may provide useful prognostic information in HIV-infected GC patients. Our findings suggest that PLR could be a valuable clinical tool for guiding treatment decisions in this population.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12876-023-02828-x.