We studied the bending strength of glued laminated beams. We add four different fibers in the adhesive bond. We used two natural fibers (flax and jute) and two synthetic (glass and carbon fibers). In test we use two types of adhesive, first is one-component polyurethane adhesive and second is melamine-urea-formaldehyde adhesive. Specimens were made from five layers of laminations and with different fibers. We conduct three point bending test according to standard SIST EN 310 and we got desired results of the bending strength and other important properties that had an effect on bending. We have found that the major impact on the bending strength have: type of fiber, the place where they are located and density of the wood. We found that some combinations with the adhesive and fiber were very good because we increase bending strength, but with some combinations with the adhesive and fiber we didn't get close to massive sample of spruce.