The health benefits of ω-3 fatty acids, particularly fish oils, are well known. It is generally recommended to obtain ω-3 fatty acids from fatty fish; however, the possible contaminants in fish products may deter this. Thus, supplements of ω-3 fatty acids from plant-originated lipids may be of interest. Among these, α-linolenic acid (ALA) and stearidonic acid (SDA) have drawn attention. Thus, the purpose of this research was to test the possible conversion of these fatty acids, particularly SDA, to eicosapentaenoic acid (EPA) using a human hepatoma cell line, HepG2 cells. In addition, even though ω-3 fatty acids have been shown to reduce hyperlipidemia, the effects on lipoprotein metabolism are relatively inconsistent. Thus, we also tested ω-3 fatty acids along with SDA on apolipoprotein A and B (apo A and B) secretion from this cell line. The results obtained suggest that both ALA and SDA were converted to EPA and they increased apo B secretion, while having no effect on apo A secretion, similar to the effects of EPA and docosahexaenoic acid. Thus, it may be concluded that SDA can be a possible candidate for use as a precursor for EPA and its effect on lipoproteins was similar to that of EPA.