The aim of this study was to investigate the effect of preoperative anemia on the prognosis of patients who underwent radical nephroureterectomy (RNU) for upper tract urothelial carcinoma (UTUC).A total of 620 patients with UTUC were retrospectively analyzed. Anemia was decided by preoperatively measured hemoglobin values based on the World Health Organization (WHO) classification. Kaplan-Meier method and Cox proportional hazards regression models were used to analyze the relationship between anemia and survival outcomes. The meta-analysis part was performed according to PRISMA guidelines.The median follow-up was 51 (range: 1-168) months. A total of 246 patients had preoperative anemia in our cohort. Anemia was found to be related to high-grade (P < .001), sessile architecture (P = .001), advanced T stage (P < .001), lymphovascular invasion (LVI) (P = .006), and worse chronic kidney disease (CKD) stage (P = .012). Kaplan-Meier curves revealed that patients with preoperative anemia had worse overall survival (OS), cancer-specific survival (CSS), and disease recurrence-free survival (RFS) (all P < .001). Multivariable Cox analyses found that anemia was an independent predictor of CSS [hazard ratio (HR) 1.719, 95% confidence interval (95% CI): 1.285-2.300], RFS (HR 1.427, 95% CI: 1.114-1.829) and OS (HR 1.756, 95% CI: 1.353-2.279). Among patients without end-stage renal disease (ESRD, n = 614), the anemia was also proved to be associated with worse outcomes in multivariable Cox analysis (OS, HR 1.759, 95% CI: 1.353-2.287; CSS, HR 1.726, 95% CI: 1.289-2.311, and RFS, HR 1.431, 95% CI: 1.117-1.837). Seven studies were included in the meta-analysis, and the pooled results showed that anemia was also related to worse CSS (HR 2.05, 95% CI: 1.73-2.44), RFS (HR 1.57, 95% CI: 1.30-1.90), and OS (HR 1.53, 95% CI: 1.10-2.13), but not related to intravesical recurrence (HR 1.17, 95% CI: 0.75-1.82).Preoperative anemia was proved to be significantly associated with worse oncologic outcomes in patients with UTUC following RNU.