Some excised specimens of upper tract urothelial carcinoma (UTUC) are concomitant carcinoma in situ (CIS). However, whether concomitant CIS affects the prognosis of UTUC is controversial. The objective of this study was to provide a comprehensive association between CIS and the prognosis of UTUC. Web of Science, PubMed, and Embase were searched to identify clinical studies about CIS and UTUC before July 2019. Newcastle Ottawa Scale was used to evaluate the quality of the literature. We calculated hazard ratios (HRs) and 95% CIs to evaluate the relationship between concomitant CIS and survival outcomes. Z test was used to pooled HRs, if P < 0.05, the difference was considered statistically significant. Total of 7,852 patients with UTUC were included, of which 1,004 (12.79%) concomitant CIS. In univariate analysis, our meta-analysis shows that concomitant CIS is associated with worse cancer-specific survival (HR: 1.54; P < 0.00001), worse recurrence-free survival (RFS) (HR: 1.42; P < 0.00001) and worse overall survival (OS; HR: 1.41; P = 0.04). In multivariate analysis, concomitant CIS is associated with worse cancer-specific survival (HR: 1.25; P = 0.004), worse recurrence-free survival (HR: 1.24; P = 0.006), and worse OS (HR: 1.12; P = 0.25), however, there was no statistical difference in the effect of CIS on OS (P > 0.05). Our meta-analysis shows that concomitant CIS is associated with worse survival outcomes in UTUC after radical nephroureterectomy. CIS is an independent prognostic risk factor in UTUC. Copyright © 2020 Elsevier Inc. All rights reserved.