Er{sup 3+}-doped SiOâ-HfOâ glassy waveguides with HfOâ concentrations ranging from 10 to 50 mol % were prepared using the sol-gel route and deposited on v-SiOâ substrates using the dip-coating technique. The local environment around Er{sup 3+} ions was determined from Er Lâ-edge extended x-ray-absorption fine-structure (EXAFS) measurements. The first coordination shell around Er{sup 3+} ions is composed of oxygen atoms. Hafnium is the main constituent of the second coordination shell of Er{sup 3+}, differing from the cases of pure SiOâ and SiOâ-TiOâ glassy hosts, in which silicon is the main atomic species. The local structure around Er{sup 3+} ions has been found to be independent on HfOâ concentration within the studied composition range. This fact implies that Er{sup 3+} ions are preferentially dispersed in HfOâ-rich regions of the glassy waveguide, even at the lowest HfOâ concentration. For all samples, no Er{sup 3+}-Er{sup 3+} coordination shell has been detected by EXAFS. The presented structural results allow us to understand some spectroscopic properties typical of Er{sup 3+}-doped SiOâ glassy waveguides co-doped with HfOâ.