ObjectiveTo systematically review the risk factors of retreatment pulmonary tuberculosis with unfavorable treatment outcome. MethodsWe electronically searched databases including CNKI, VIP, CBM and WanFang Date from inception to November 15th 2015, to collect studies about the risk factors of retreatment pulmonary tuberculosis patients with unfavorable treatment outcome. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies. Then, meta-analysis was conducted using RevMan 5.3 software. ResultsA total of 13 studies were included. The results of meta-analysis showed that significant association was found between retreatment pulmonary tuberculosis cases with unfavorable treatment outcome and such factors as the standard retreatment regimen (OR=4.98, 95%CI 2.95 to 8.39, P < 0.00001), drug-resistance (OR=4.22, 95%CI 1.85 to 9.63, P=0.0006), multi-drug resistance (OR=7.19, 95%CI 2.51 to 20.58, P=0.0002), status of cavitas (OR=1.80, 95%CI 1.20 to 2.71, P=0.005), TB-diabetes mellitus (OR=2.05, 95%CI 1.30 to 3.22, P=0.002) and high sputum smear load >2+(OR=2.07, 95%CI 1.30 to 3.29, P=0.002) in univariate-analysis, respectively. But, in multivariate-analysis, only TB-diabetes mellitus (OR=3.38, 95%CI 1.56 to 7.29, P=0.002) showed significant association with retreatment pulmonary tuberculosis cases with unfavorable treatment outcome. ConclusionCurrent evidence shows that TB-diabetes mellitus, standard retreatment regimen, drug-resistance, multi-drug resistance, status of cavitas and high sputum smear load >2+ are considered to be the risk factors for retreatment pulmonary tuberculosis cases with unfavorable treatment outcome. Especially, for patients with diabetes, the importance of management need to be reinforced to reduce the failure rate in the retreatment of pulmonary tuberculosis. Due to limited quality and quantity of the included studies, more high quality studies are needed to verify the above conclusion.