Caffeic acid (CA) is a hydroxycinnamic acid, a group of natural organic phenolic compounds used in folk medicine and in foods for the prevention and treatment of obesity. CA is present in a variety of plants, as it is an intermediate in secondary metabolism. It is found in coffee, wine and olive oil. The aim of this work was to study the influence of caffeic acid (CA) on the reduction of intracellular lipid accumulation, intracellular reactive oxygen species (ROS) formation and in mitochondrial transmembrane potential alterations in differentiated 3T3-L1 cells. The pre-adipocyte cell line 3T3-L1 was differentiated using a differentiation cocktail. Cells were treated with CA, and the MTT assay was performed to assess the effect of CA on pre-adipocytes. The quantification of lipids accumulated within the mature cells was performed using Oil Red O dye. Flow cytometry was used to evaluate the production of ROS through 2',7'-dichlorofluorescein diacetate (DCFH-DA) oxidation and changes in mitochondrial transmembrane potential by Rhodamine 123 dye (Rho123). CA did not exhibit significant toxicity on the 3T3-L1 cell line at the studied concentrations. Caffeic acid causes significant reduction of lipid content in the cells submitted to the post-and co-treatment, being more effective in cotreatment. Caffeic acid results in an absolute decrease in the formation of intracytoplasmic reactive oxygen species. The treatment with caffeic acid protects against oxidative stress caused in the mitochondria by the adipocyte differentiation process. Thus, CA acts on adipogenesis, reducing intracellular lipid accumulation in the 3T3-L1 cells. It reduces intracellular ROS formation and mitochondrial transmembrane potential alterations in differentiated cells.