The potential of membrane-assisted dewatering was evaluated on a laboratory suction box. Different membranes, one impermeable and two permeable membranes were placed on top of the wet web, while a suction pulse was exerted underneath the web. The deformation of the wet web and the dry content of the web were determined approx. 30 seconds after the suction pulse. The results of these experiments were compared with results of those carried out without a membrane. A significantly higher web compression was observed at the end of the suction pulse when a membrane was used. The increased web compression that occurred when using a membrane corresponded to a dry content of 3 to 4%. The highest dry content values were obtained, however, when no membrane was applied. This contradiction was interpreted as a higher rewetting after the suction pulse when a membrane was used. Here, due to the reduced air flow through both the web and the forming fabric, it is likely that more water was available in the forming fabric for rewetting. Apparently, the air flow removed water from the forming fabric that otherwise would have been rewetted by the web.