In order to reduce the consumption of energy and the emissions of greenhouse gases and CO 2 generated by the construction industry, bio-based concretes made of plant aggregates are increasingly used in the optimization of building envelopes thanks to their good hydrothermal performances, their renewable origin, and biodegradability. These insulation materials are considered as a promising alternative to synthetic systems made of mineral wool. This study investigates the use of a bio-based concretes performed with a mixture of eco-aggregates derived from rice plant and lime as thermal insulation materials. The effect of combining different proportions of rice straw (RS) with rice husks (RH) (100%, 66%, 50%, and 33%) on both mechanical and hydrothermal properties of bio-based concretes are investigated. The characterization seeks to evaluate the thermal conductivity, moisture buffer value (MBV) and mechanical compressive properties of the rice straw/rice husk concretes. Results show that the thermal conductivity of the bio-based concretes slightly decreased with increasing rice straw content. The MBV values measured showed that rice straw confers to concretes an excellent moisture buffering capacity according to the Nordtest project classification. The compression test result also revealed that rice straw concretes have high mechanical deformability. Straw concretes do not break but continuously deform.