This paper describes the implementation of a digester chip level control system at the M-real Husum mill and an analysis of the chip level control problem. The kappa number variability is strongly related to variability in chip transport conditions which is related to the variations in chip retention time, caused by fluctuations in chip packing, blow line consistency, etc. It is important for a uniform pulp quality to have a stable movement of the chip column and stable properties in digester bottom. The objective with implemented chip level control system is to stabilize the transport conditions in the bottom of the digester by using the chip feed and not the blow flow (original control system) as the primary manipulated variable. The results indicate a smoother digester operation and a reduction of kappa number variations. The level control strategy is implemented both as a MPC controller scheme on a stand alone PC and as a conventional PID-solution in the DCS system.