It has been reported that methylated analog of resveratrol, 3,4,5,4'-trans-tetramethoxystilbene (DMU-212), demonstrates strong antiproliferative, and proapoptotic activity. The aim of this study was to evaluate the effect of DMU-212 on the activation of nuclear factor-κB (NF-κB), activator protein-1 (AP-1), and signal transducer and activator of transcription 3 (STAT3) transcription factors, using a two-stage model of rat hepatocarcinogenesis (HCC) in Wistar rats. Initiation was performed by a single intraperitoneal injection of N-nitrosodiethylamine (NDEA) (200 mg/kg) followed by promotion with phenobarbital (PB) (0.05%) in drinking water. DMU-212 was administered by gavage in a dose of 20 or 50 mg/kg b.w. two times a week for 16 weeks. There was a significant increase in the activation of all investigated hepatic transcription factors in the NDEA/PB-induced rats. The activation of NF-κB induced by NDEA/PB treatment was suppressed by DMU-212 as evidenced by a reduction of p65 and p50 subunits translocation, DNA binding capacity, increased retention of IκB, and the reduced IKK activity. Moreover, DMU-212 reduced the level of iNOS protein induced by NDEA/PB. Treatment with DMU-212 alone increased the constitutive AP-1 subunits c-Jun and c-Fos levels and c-Jun binding to TRE consensus site. The combined treatment diminished c-Fos level and DNA binding. At a dose of 50 mg/kg, DMU-212 decreased also the STAT3 activation induced by NDEA/PB. These data indicate that DMU-212 may suppress pro-inflammatory transcription factors, particularly NF-κB, and in consequence iNOS expression in rat model of HCC which makes DMU-212 a good candidate for the development of HCC chemopreventive agent.