An active vibration isolation system comprising a) a support body for bearing a load which is to be isolated, b) pneumatic vibration isolators with controllable valves for carrying the support body with respect to a base, c) position sensors for providing vertical position signals of the support body, d) a first regulating system for vibration compensation in at least one degree of freedom in translation (Xt,Yt,Zt) and in at least one degree of freedom in rotation (Xr,Yr,Zr) with at least d1) first sensors (6,7,8,9,11) for providing first sensor signals which represent vibrations, d2) first actuators for vibration compensation which are controllable by feeding first actuator actuation signals, and d3) a first regulating device which is intended to process the provided first sensor signals to form the first actuator actuation signals, and e) a second pneumatic regulating system for vibration compensation in at least one degree of freedom selected from three degrees of freedom (Zt,Xr,Yr) which are effective in vertical direction with at least e1) the position sensors as second sensors for providing second sensor signals which represent vibrations, e2) the pneumatic vibration isolators with the valves as second actuators for vibration compensation which are controllable by feeding second actuator actuation signals, and e3) a second regulating device which is intended to process the provided position signals to form the second actuator actuation signals, characterized in that at least one branch from the first regulating system to the second pneumatic regulating system is provided such that the first regulating system and the second pneumatic regulating system are coupled to act together in at least one degree of freedom of the three degrees of freedom (Zt,Xr,Yr) which are effective in vertical direction. a) a support body for bearing a load which is to be isolated, b) pneumatic vibration isolators with controllable valves for carrying the support body with respect to a base, c) position sensors for providing vertical position signals of the support body, d) a first regulating system for vibration compensation in at least one degree of freedom in translation (Xt,Yt,Zt) and in at least one degree of freedom in rotation (Xr,Yr,Zr) with at least d1) first sensors (6,7,8,9,11) for providing first sensor signals which represent vibrations, d2) first actuators for vibration compensation which are controllable by feeding first actuator actuation signals, and d3) a first regulating device which is intended to process the provided first sensor signals to form the first actuator actuation signals, and d1) first sensors (6,7,8,9,11) for providing first sensor signals which represent vibrations, d2) first actuators for vibration compensation which are controllable by feeding first actuator actuation signals, and d3) a first regulating device which is intended to process the provided first sensor signals to form the first actuator actuation signals, and e) a second pneumatic regulating system for vibration compensation in at least one degree of freedom selected from three degrees of freedom (Zt,Xr,Yr) which are effective in vertical direction with at least e1) the position sensors as second sensors for providing second sensor signals which represent vibrations, e2) the pneumatic vibration isolators with the valves as second actuators for vibration compensation which are controllable by feeding second actuator actuation signals, and e3) a second regulating device which is intended to process the provided position signals to form the second actuator actuation signals, e1) the position sensors as second sensors for providing second sensor signals which represent vibrations, e2) the pneumatic vibration isolators with the valves as second actuators for vibration compensation which are controllable by feeding second actuator actuation signals, and e3) a second regulating device which is intended to process the provided position signals to form the second actuator actuation signals,