A composite doctor blade chamber (1) for a doctor blade chamber system for rotary printing units, the doctor blade chamber (1) including a front side with an open channel (8), wherein the doctor blade chamber is made of two composite profiles, an open profile (30) with a front side and a back side and a closed profile (33) with a front side and a back side, wherein the front side (31) of the open profile is joined with the back side of the closed profile (35), whereby is achieved low weight and high strength, high corrosion resistance, a cleaning-friendly surface, less waste of ink, nice appearance and an improved working environment. In addition it is an object of the invention to provide a doctor blade chamber system with the above mentioned advantages where re placement of doctor blades can be performed faster, more easily and without use of tools.