Växjö university has together with Södra developed a new green-glued laminated beam, which to be used in a building system. To make a product of the beam it is desired to also develop a building system based on the beam. An important part of such a building system is the connections. The main aim of the thesis was to design a new beam-to-beam connection in for the new green-glued laminated boards. This thesis is about to develop and test a new connection for a beam-to-beam connection in the building system. The requirements set on the connection was that it should be used in an office building with a beam length of 6 m, the connection should be fast to assemble and invisible. The report thoroughly describes the conceptual design, the development and test of the connection. Five different types of connections were designed in the conceptual design phase. One of these connections fulfilled the requirements and was taken to the development and testing phase. Three versions of the connection were tested. The report describes how the green-glued laminated beams with the connections were tested in a testing machine until the failure occurs. The developed connection could fulfil the requirements set on the connection. One version of the connection was even stronger than the green-glued laminated beams.