Some of the main properties of polysaccharide and protein-based aerogels are discussed in this chapter. The fundamentals of thermal conductivity governing the insulation properties of these materials are presented and related to the aerogel microstructure. In particular, obtaining aerogels with evenly distributed nanometric pore sizes is crucial to decreasing the thermal conductivity and to achieve super-insulation materials. Secondly, an insight into the different approaches that can be used to impart electrical conductivity or magnetic properties of bio-based aerogels is highlighted. Apart from the addition of different conductive fillers traditionally used as a second phase, the synthesis with conductive polymers and the conversion of the aerogel structure in a conductive carbon-based path enables the formation of aerogels with a wide range of electrical properties. Finally, this chapter focuses on the fire behavior of polysaccharide and protein aerogels. The basic carbohydrate structure presents a serious challenge when trying to prevent fast combustion, especially in aerogels formed from polysaccharides. However, the development of hybrid organic–inorganic systems using graphene, silicon, clay or their combination with intrinsically flame-retardant materials, such as alginates, are powerful tools in the design of aerogels with low flammability and potential industrial applications