<p>With their hydrophobic properties, microplastics can disperse in water, carrying pollutants such as heavy metals, including cadmium (Cd), a non-essential metal that can cause oxidative stress and cell death in fish. Therefore, this study evaluated the effects of single and combined exposure to polystyrene microbeads (MBs) and Cd on their accumulation, oxidative stress status, and apoptosis in <i>Sebastes schlegeli</i>. The results revealed that the accumulation of MBs and Cd in the gills and intestines increased, and the mRNA expression of copper-zinc superoxide dismutase, catalase, and cytochrome P450 family 1 subfamily A polypeptide 1 in the liver was confirmed. Furthermore, caspase-3 mRNA expression and TUNEL analyses demonstrated that liver H₂O₂ and plasma malondialdehyde levels and apoptosis significantly increased following combined MB and Cd exposure. The study suggests that the combination of hydrophobic MBs and Cd can increase their accumulation in <i>S. schlegeli</i>, leading to oxidative stress and apoptosis. This combination of external toxic substances, such as Cd, with microplastics can negatively impact aquaculture and potentially affect humans.</p>