A potential but an underexplored application of FIB_SEM is its ability to image the subsurface microstructure and capability for an associated chemical analysis. In this article, agglomerated microstructures of two model oxide dispersion strengthened alloy systems, consisting of ZrO 2 and Y 2 O 3 dispersions, are evaluated to understand its elevated temperature behaviors. The systems under evaluation are relevant as candidate nuclear structural materials for next-generation fast breeder reactors, and FIB_SEM technique is effectively used along with TEM and EDS for a comprehensive understanding of the material microstructure, and the results are discussed. Distinct microstructures are observed for the two systems with a difference in crystallite size distribution and presence of micron-sized dispersoids in Y 2 O 3 . The varied behavior of dispersoids is discussed in terms of its pre-annealing microstructures, and the superiority of ZrO 2 over Y 2 O 3 as a dispersoid for ODS alloys is emphasized.