AbstractThe present status of in‐situ scanning transmission X‐ray microscopy (STXM) is reviewed, with an emphasis on the abilities of the STXM technique in comparison with electron microscopy. The experimental aspects and interpretation of X‐ray absorption spectroscopy (XAS) are briefly introduced and the experimental boundary conditions that determine the potential applications for in‐situ XAS and in‐situ STXM studies are discussed. Nanoscale chemical imaging of catalysts under working conditions is outlined using cobalt and iron Fischer–Tropsch catalysts as showcases. In the discussion, we critically compare STXM‐XAS and STEM‐EELS (scanning transmission electron microscopy–electron energy loss spectroscopy) measurements and indicate some future directions of in‐situ nanoscale imaging of catalytic solids and related nanomaterials.