In patients with acute nonvariceal upper gastrointestinal bleeding (ANVUGIB), the optimal timing of endoscopy is still a matter of dispute. We conducted a systematic review and meta-analysis to determine the clinical benefit of early endoscopy.A literature search of the MEDLINE, Embase, and Cochrane databases was conducted to identify publications from inception to March 1, 2022. Eligible studies included observational cohort studies and randomized controlled trials that reported clinical outcomes of endoscopy in patients with ANVUGIB. ANVUGIB patients who underwent endoscopy within 24 hours of admission were considered to have had an early endoscopy. The primary outcome was the mortality rate in ANVUGIB patients who had early or nonearly endoscopy.The final analysis included five randomized controlled studies (RCTs) and 20 observational studies from the 1,206 identified articles. The mortality rate was not significantly reduced among patients who received endoscopy performed within 24 hours, whether in cohort studies nor in RCTs. For subgroup analysis, a higher mortality rate was found only among patients who received very early endoscopy within 12 hours (odds ratio, 1.66; p<0.001, I2=0) in cohort studies. No significant difference in mortality rates was found among patients at high risk of bleeding who received early versus nonearly endoscopy.Early endoscopy within 24 hours does not appear to significantly reduce the mortality rates of patients with ANVUGIB. Further well-designed studies are warranted to address if very early endoscopy within 12 hours can provide a clinical benefit for patients at high risk of bleeding.