Although various studies have been published regarding the treatment of chronic hepatitis C (CHC) with peginterferon (Peg-IFN) and ribavirin, little is known regarding the real impact of gender on the characteristics that influence the effectiveness and safety of antiviral treatment for CHC patients. The objective of this study was to evaluate the influence of gender on HCV treatment outcomes. A retrospective analytical study was conducted among selected carriers of CHC genotype 1, who were treated with Peg-IFN alpha-2b at a dose of 1.5 microg/kg or Peg-IFN alpha-2a at a dose of 180 microg/week plus a ribavirin dose of 1,000-1,250 mg/day, according to weight, between 2001 and 2007. Among 181 patients undergoing treatment, the mean age was 46.4 +/- 11.0 years and 46% were women. At baseline, 32% of the patients had advanced fibrosis (F3-F4 Scheuer), and 83% of the subjects had viral load > 400,000 IU/ml, without significant difference between the genders (p = 0.428 and p = 0.452, respectively). When compared with men, women had higher incidence of many adverse events such as anemia (p < 0.001) and higher need for dose reduction, for both Peg-IFN (p = 0.004) and ribavirin (p = 0.006). However, the rate of sustained virological response (SVR) did not differ between the genders: 45% (female) vs 41% (male); p=0.464. This study suggests that women and men react differently to combined therapy, especially in relation to the incidence of adverse events and the need for dose modification. Nevertheless, these differences do not influence the SVR rate.