The expression of macrophage inhibitory factor-1 (MIC-1) increases in patients with chronic hepatitis C (CHC), but whether MIC-1 level and its polymorphism affect the antiviral efficacy of CHC has not yet been reported. The present study aimed to investigate the association between MIC-1 polymorphism and antiviral efficacy in patients with CHC genotype 1b (CHC 1b). A total of 171 patients with CHC1b were recruited. The polymorphisms of rs1059369 and rs1059519 in MIC-1 were detected by DNA sequencing. All patients received a standard dose of polyethylene glycol interferon + ribavirin (PR regimen), and divided into response, nonresponse, sustained virological response (SVR), and non-sustained virological response (NSVR) groups based on HCV RNA levels. The genotype distribution of the two single nucleotide polymorphisms (SNPs) did not differ between the response and nonresponse groups, SVR and non-SVR groups. However, the level of MIC-1 was positively correlated with ALT, AST, PIIINP, CIV, and HCV RNA (P < 0.05). Compared to before treatment, the level of MIC-1 in plasma was significantly decrease in the response group but not in the non-responsive group. Our results suggest that the level of MIC-1 in CHC1b is correlated with liver cell injury, liver fibrosis index, and viral load. However, the polymorphism of rs1059369 and rs1059519 may have negligible impact in expression of MIC-1 and efficacy of antiviral therapy in CHC patient.