In an attempt to accurately predict the implications of steel corrosion on the long-term durability of reinforced concrete structures, the literature still reveals a lack of understanding of several multi-scale processes occurring at the steel-concrete interface (SCI) relevant to steel reinforcement corrosion. Among other open questions, recent studies have highlighted the need to elucidate in depth aspects such as the microstructure, pore structure, and phase assemblage of the SCI, as well as the characteristics of the corrosion products precipitating therein. To this end, this study reports on the application of Focused Ion Beam – Scanning Electron Microscopy (FIB-SEM) on one polished section of corroding reinforced concrete specimen to investigate potential to characterize the micro-scale porosity and the micro-structure of corrosion products precipitated in interfacial macropores (e.g., voids) and within the surrounding concrete matrix. The obtained spatial resolution (i.e., pixel size of 20 nm) allowed for the observation of the porous network of the concrete matrix around the interfacial void, as well as that of the corrosion products phases precipitated along the walls of the void. Through the performed FIB-SEM analysis, distinct layers of corrosion products, differentiated by morphology and chemical composition, were found at the walls of the void, filling the void inwards. The potential of this technique to elucidate several open questions is discussed, and ongoing and future work in line with this study is finally described.