A UV-vis microspectroscopy methodology for monitoring the speciation and macrodistribution of catalyst-precursor species inside catalyst-support bodies at the initial stages of catalyst preparation has been developed. The setup is based upon optical-fiber technology and allows spatially resolved analysis of bisected catalyst bodies. The potential of this tool is demonstrated by two pore-volume impregnation studies involving Ni2+ d-d transition bands and Cr6+ charge-transfer bands.