Ni-YSZ anode supports were used to fabricate test cells composed of yttria-stabilised zirconia (YSZ) electrolyte and lanthanum strontium ferrite (LSF) or lanthanum strontium manganite (LSM) / YSZ cathodes. These cells were operated at 720 °C at an average current density of 0.28 to 0.46 A/cm2. A central piece of selected anode support was extracted from tested cells and characterized using a transmission x-ray microscope (TXM). Using differential absorption imaging across the Ni K-absorption edge (8.333 keV) along with x-ray nanotomography, the 3D distribution of the Ni, YSZ, and pore phase diameters in the SOFC anode were characterized at various operational times. Significant microstructural change was observed in the Ni phase. Such an observation suggests that the microstructural reconfiguration of the phases may be correlated to SOFC performance, and may elucidate underlying fundamental mechanisms that induce such changes.