Biobased concretes, such as flax or wood concretes, are ecofriendly materials that benefit excellent hygrothermic and acoustic properties. They are usually combined with a loadbearing wooden structure, but recent studies show that those concretes can reach masonry-like compressive strengths, which suggests their potential use for structural elements. However, the lack of data on its delayed mechanical behavior is an issue to their development. This article describes the study of the drying and shrinkage, in controlled environments (22 ℃, 50%RH), of two types of biobased concrete: flax concrete and wood concrete. The water loss and shrinkage of concrete samples are monitored for one month under autogenous and drying conditions. The strength of the concretes, and the cement paste alone, are also tested at different ages. Results show that wood concrete is the most suited for structural use thanks to its higher mechanical strength. Besides, the lower water absorption capacity of wood aggregates makes wood concrete less demanding in water during its fabrication than flax concrete. Finally, the shrinkage of wood concrete is 3.5 times lower than flax concrete after one month.