Objective To investigate the significance of T-bet and GATA-3 in the pathogenesis of pityriasis rosea.Methods SYBR Green Ⅰ real-time fluorescence quantitative PCR was performed to detect the expressions of T-bet and GATA-3 mRNA in peripheral blood mononuclear cells (PBMCs) from 17 patients with pityriasis rosea and 20 normal human controls.Results The average delta Ct value of T-bet mRNA and GATA-3 mRNA was 3.33 ± 0.94 and 5.22 ± 0.69 respectively in the patients,4.31 ± 1.11 and 4.36 ± 1.02respectively in the controls.There was a higher expression of T-bet mRNA but a lower expression of GATA-3 mRNA in the patients compared with the controls (both P ＜ 0.05).Conclusions Patients with pityriasis rosea show an increased ratio of T-bet to GATA3 expression and predominant expression of Th1-type cytokines.Abnormal cellular immunity may play an important role in the pathogenesis of pityriasis rosea.