The mechanical strength of oxide dispersion strengthened (ODS) ferritic steels depends on the oxide particles, such as Yttria. Other elements such as titanium and aluminum are added to refine the dispersed particles of ODS steels. The addition of elements results in the formation of complex oxides such as (Y, Al) and (Y, Ti) oxides. Because the ODS steels are proposed for the higher temperature operation of fusion applications, the stability of the complex oxides under irradiation environments is important. In this work, a microstructural stability investigation under heavy-ion irradiation was carried out for ODS steels focusing on the morphology of (Y, Ti) and (Y, Al) complex oxides. The 19Cr ODS steel strengthened by (Y, Ti) complex oxides and 19Cr-2W-4Al steel with (Y, Al) complex oxides were ion-irradiated and investigated using TEM. The results revealed that the complex oxides were stable after the ion irradiation at 670 °C and 150 dpa.