Thesis researches how the structure of a wood-based panel influences the fracture when loading the panel with a maximum bending force. Wood-based panels such as plywood, OSB, constructional, particleboard and fibre board panels, available on the market, were tested. We studied how the appearance of a fracture and mechanic characteristics of a particular layer influence the entire panel. The fracture of a transversal plywood panel is straight while the one of a longitudinal panel is jagged and follows the structure of wood. The fracture of a surface layer of an OSB panel is jagged while the course of a fracture inside the panel is straight. The most homogeneous fracture in all layers of a panel was noticed at LSB - constructional panel where the fracture took place among the components and was jagged. The surface layer of a particleboard with higher density and smaller parts has a straighter fracture, while the interior layer with lower density and larger parts has a more jagged structure. Smaller the parts, straighter the fracture; the fibres excluded. A fibre board (MDF) has an extremely jagged fracture at all layers and it is similar to the fracture of a longitudinal plywood panel. The test shows that individual layers of a fibre board are relatively weak, but all together they form a panel with best characteristics.