Objective: The objective was to investigate the anti-lipidemic and anti-inflammatory effects of genistein on rats with estrogen deficiency and nonalcoholic steatohepatitis (NASH). Materials and Methods: Sprague-Dawley female rats (n = 48) were randomly divided into ovariectomized (OVX) and non-OVX groups, then again divided into three subgroups as follows: controls, rats fed with high-fat high-fructose (HFHF) diet (NASH group), and rats fed with HFHF diet plus daily 16 mg/kg genistein (genistein group). Liver tissues were used for histology, liver tissues were used for histology and measured of hepatic free fatty acid (FFA) by colorimeter, and nuclear factor kappa B (NFκB) expression by immunohistochemistry. Serum tumor necrosis factor-α (TNF-α) was evaluated by enzyme-linked immunosorbent assay. Results: NASH group had increased serum TNF-α (171.62 ± 22.34 vs. 58.47 ± 14.83 pg/mL), %NFκB-positive cells (53.94 ± 11.89 vs. 13.73 ± 3.40), and hepatic FFA (9.07 ± 2.27 vs. 3.62 ± 0.77 nmol/mg tissue) when compared with control (P < 0.01). The most severe hepatic fat accumulation and inflammation was found in OVX with NASH group. Genistein treatment decreased serum TNF-α compared with NASH groups in both non-OVX and OVX groups (105.84 ± 29.77 vs. 171.62 ± 22.34 pg/mL and 73.07 ± 19.31 vs. 124.12 ± 16.04 pg/mL, respectively) (P < 0.01). Genistein reduced %NFκB-positive cells in NASH rats (31.84 ± 10.60 vs. 53.94 ± 11.89) and decreased hepatic FFA levels in OVX with NASH rats (6.50 ± 0.60 vs. 13.11 ± 1.65 nmol/mg tissue) when compared with NASH group, respectively (P < 0.01). Conclusion: Estrogen deficiency is the contributing factor that worsens NASH. Genistein attenuated hepatic fat accumulation and inflammation. Moreover, genistein demonstrated to be more effective in estrogen deficiency with NASH than ovary-intact rats.