The present invention relates to a system (1) having hybridization chambers (5) for hybridizing nucleic acid samples, proteins, or tissue sections immobilized on slides (27), each hybridization chamber (5) being defined as an essentially gap-shaped chamber, which is essentially fillable with a liquid, between one of these slides (27) and a cover (26), and the cover (26) being positioned in relation to the slide (27) in such a way that the hybridization chamber (5) is sealed to the surrounding air, the system (1) including a device for preventing air bubbles in the hybridization chambers (5). The system according to the present invention is distinguished in that this device for preventing air bubbles in the hybridization chambers (5) is implemented as a pressure device to build up a chamber pressure in the hybridization chambers (5), this chamber pressure lying above the normal atmospheric pressure existing in the surrounding air. The present invention additionally relates to a method for preventing air bubbles in the hybridization chambers (5) of such a system (1) and is distinguished in that, using a pressure device of this system (1), a chamber pressure is implemented in the hybridization chambers (5) which lies above the normal atmospheric pressure existing in the surrounding air.