Abstract Objectives Doenjang, the Korean traditional fermented soybean paste, contains much salt. There is a concern that cardiovascular disease may occur due to such high salinity. Nevertheless, previous studies have demonstrated functional properties of doenjang anti-obesity and anti-cancer effects. Furthermore, in our recent studies, we showed that the anti-hypertensive effect of doenjang through renin-angiotensin system (RAS) regulation. Doenjang regulated the RAS to improve lipid metabolism in adipose tissue, which had a positive effect on blood pressure control. Therefore, we expected to find the exact mechanism of action or target point of doenjang in adipocyte using 3T3-L1 cells. Methods In this study, 3T3-L1 cells were treated with doenjang and RAS blockers, Losartan (10−4 M), and Captopril (10−4 M), were treated as positive control which suppresses AT1R and ACE, respectively. Non-cytotoxic concentrations of samples were selected as per MTT assay and added with induction media, harvested after 4 days for RNA extraction. Lipid droplets were detected by Oil Red O staining. Results Doenjang downregulated mRNA levels of peroxisome proliferator-activated receptor-γ (Pparg), RAS related genes such as angiotensinogen (Agt), Renin (Ren), and aldosterone-releasing factors (P < 0.05). Especially, angiotensin convert enzyme (Ace) and angiotensin II receptor 2 (Agtr2) levels were decreased by doenjang treatment. Doenjang reduced the lipid accumulation, which was confirmed from the Oil Red O staining of lipid droplets. As a result, it is revealed that doenjang not only inhibits lipid accumulation in adipocytes but also may inhibit ACE in 3T3-L1 adipocytes through a mechanism similar to the effect of Captopril. Conclusions These data are consistent with our animal study. It have been shown to regulate blood pressure through lipid improvement and ACE inhibition despite high salt content in doenjang. Funding Sources This work was supported by the Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government (MEST) (No. 2018R1A2B6006477).