Dry and mixed reforming of methane (DRM and MRM) are candidate routes for the production of synthesis gas. By this way, two Greenhouse gases CH4 and CO2 can be effectively valorised. In the present work, activity trials were performed in a fixed bed reactor using commercial Ni/Al2O3 catalyst. The reaction variables were so varied: temperature 773 -1073 K, space time 0.08-0.33 g h/L, CO2/CH4 0.5-2 mol/mol (for DRM) and steam/carbon ratio 0.2-0.5 mol/mol (for MRM). The dependency of CH4 and CO2 conversions, H-2 and CO yields and syngas ratio on the reaction conditions was studied. The best conditions for stoichiometric feed composition were 0.25 g h/L space time at 1073 K temperature, wherein CH4 and CO2 conversions were 90 and 85.7% for DRM and 83 and 78.2% for MRM. After 10 h time-on-stream, the carbon deposition rate over Ni/Al2O3 was 22.7 and 20.4 mg/g(cat)/h for DRM and MRM correspondingly. The role of secondary reactions in the DRM and MRM process was elucidated. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.