This study deals with the reuse of sugarcane bagasse in adobes in order to improve their physicomechanical properties. Mineralogical and geotechnical characterization of the soil used shows that it is composed of quartz, kaolinite and goethite and is suitable for the manufacture of adobes. Sugarcane bagasse has a rough surface and contains mainly cellulose, hemicelluloses, lignin and traces of sucrose. Microstructural studies on adobes reinforced with sugarcane bagasse have shown that their microstructure is homogeneous for additions of these fibres up 4 wt.%. It has been found that the addition of sugarcane bagasse to the clayey matrix strongly improves the mechanical properties and reduces the water absorption kinetics and thermal conductivity (mainly because of the presence of cellulose) of the adobes, linked to their microstructure. The rough surface of sugarcane bagasse and the presence of sucrose acting like glue improve its adhesion with the clayey matrix, and cracks propagation in adobes is reduced. The presence of bagasse fibres leads to the formation of hydrogen bonds between sugarcane molecules and the clayey minerals, which could explain the improvement in the physicomechanical properties. Considering the thermal conductivity results, such adobes could improve the thermal comfort in habitats, especially in arid areas.