What is known and objectives The association between inosine triphosphatase (ITPA) rs1127354 polymorphisms in HCV-infected patients receiving ribavirin (RBV)-based therapy, and the risk of adverse drug reaction and outcomes is still unclear. A meta-analysis was conducted to summarize and clarify this association systematically. Methods A comprehensive search was performed in PubMed, Embase and Web of Sciences, and twenty-two studies were selected from the literature search. Pooled odds ratio (OR) and 95% confidence interval (95% CI) were estimated by either fixed- or random-effects models. Results Four outcomes were evaluated: (a) haemoglobin decline: significant associations with haemoglobin decline were found for rs1127354 CC VS CA + AA (OR = 10.59, 95% CI = 6.39-17.54); (b) severe anaemia: significant association with severe anaemia was observed for rs1127354 CC VS CA + AA (OR = 16.24, 95% CI = 6.21-42.43); (c) sustained virological response (SVR): CC genotype carriers had a decrease SVR during treatment (OR = 0.65, 95% CI = 0.52-0.81); (d) RBV dose reduction or stopping treatment: although statistical evidence of an association was found between the polymorphism and RBV dose reduction during treatment (OR = 1.80, 95% CI = 1.03-3.13), the sensitivity analysis suggested this result was not robust. What is new and conclusion Patients with ITPA rs1127354 CC polymorphism are more likely to develop haemolytic anaemia, severe anaemia and decreased SVR. Testing for this genetic polymorphism may benefit patients.