Various biomaterials with unique characteristics are developed routinely for tissue engineering applications; still, but their mechanical behaviour is not always fully investigated that can affect their potential applications.One example is bacterial cellulose (BC) hydrogel.Its biocompatibility makes it a potential candidate for different applications in biomedical engineering.For instance, it can be used as a scaffold for regenerating soft tissues.To allow such applications, the mechanical behaviour of BC hydrogel should be fully understood.It is well-known that the materials performance is linked to its microstructure; on the other hand,microstructural changes under various loading conditions are crucial for understanding its mechanical behaviour.Structurally, the BC hydrogel is composed of a multi-layered nanofibre network and a high content of interstitial water.Its mechanical properties are well documented, but few studies investigated systematically its deformation mechanisms under tensile and compressive loading regimes.In this study, in aqua uniaxial tension and compression tests with image recording were performed at a constant temperature of 37℃ to mimic the human body environment in order to determine the microstructure-mechanical behaviour relationship.