The catalytic oxy-CO2 reforming of biogas (a combination of partial oxidation and dry reforming reactions) was studied with various Rh-based catalysts prepared in the laboratory using different supports: gamma-Al2O3, SiO2 and CeO2. Their performance was compared to a commercial Rh/Al2O3 catalyst serving as reference. Different O-2/CH4 ratios were studied: 0 (dry reforming), 0.10, 0.20 and 0.45. In all cases, both laboratory-prepared and commercial Rh/Al2O3 catalysts clearly outperformed the others, including a Pt commercial catalyst tested under dry reforming conditions. It could be established that the catalytic performance of the Rh-based catalysts prepared by impregnation on different supports had the following decreasing order: Rh/Al2O3 > Rh/SiO2 > Rh/CeO2. Equilibrium conditions could be achieved through 2 h of dry reforming of biogas at 700 degrees C using the Rh commercial catalyst at gas hourly space velocities (GHSV) of 30 N L CH4/(g(cat).h). Higher GHSV values (150 and 300 N L CH4/(g(cat).h)) resulted in a slow decay of the activity over time, more accentuated at the most severe space velocity condition. However, the decrease in methane conversion and H-2 yield was milder when oxy-CO2 reforming conditions were used. Adding O-2 to the reactor feed was proven beneficial, enhancing initial and overall CH4 conversions as well as hydrogen yields, which followed an increasing trend with increasing O-2/CH4 ratios in all cases. The characterization of the spent samples under dry reforming conditions revealed the presence of carbon deposits of predominantly polymeric nature, though co-existing with other types of coke. These promising results pave the path for developing highly active and stable catalytic formulations for producing syngas by means of oxy-CO2 reforming of biogas with Rh-based catalysts.