The abdominal compartment syndrome (ACS) is a clinical condition characterized by an increase of abdominal pressure which needs prompt abdominal decompression. The surgery of large abdominal hernias can present similar problems with an increased abdominal pressure at peritoneal closure which needs a prosthetic tension-free abdominal closure to correct the increased respiratory work-load. We undertook a study in order to compare the respiratory mechanical work-load changes during the surgery of large abdominal incisional hernias and the ACS. We measured the static compliance of the entire respiratory system (Crs), and its components-lung (CL) and chest-wall (Ccw)-during the acute phase of increased abdominal pressure and after decompressive treatment. In ACS the baseline measurements of Crs, CL, Ccw were 0.034, 0.049 and 0.115 L/cmH20 respectively; after decompression treatment we observed a great increase of Ccw (0.167 L/cmH2O) whereas Cl remained the same (0.O49L/cmH2O); Crs varied from 0.034 to 0.038 L/cmH2O. In the surgery of large laparoceles, the Crs changed from 0.048 to 0.046 and the Ccw from 0.150 to 0.180, with an unchanged Cl. We conclude that the abdominal compartment syndrome is characterized by a well-defined alteration of respiratory work-load (decrease of chest-wall compliance), and that from a mechanical point of view there is only a quantitative difference if compared to large ventral hernia repair. The decrease of chest-wall compliance in the latter is less severe and statistically different (p = 0.002).