A method for the return of blood from a blood treatment apparatus, preferably from a dialysis apparatus, uses a pumped substituate fluid to displace the blood. A substituate pump contained in the treatment apparatus displaces the blood by means of the correspondingly transported substituate fluid until it is detected in corresponding detectors that substituate fluid is flowing back in the line instead of blood. Once the transported substituate fluid has been detected, the blood volume is further displaced in a controlled manner until it has reached the line outlet of the corresponding line.