We performed an open experimental study for evaluation of rapidly absorbable material of bovine serosa for diaphragm replacement. A total of 100 Sprague-Dawley rats were randomly assigned to five groups of equal size. In the control group (n=20) incision of the diaphragm was followed by primary suture. The animals of the four other groups underwent partial resection of the left hemidiaphragm. The defects were repaired by lyophilized dura, polytetrafluorethylene (PTFE), autologous transversus muscle or rapidly absorbable bovine serosa. We performed electromyography (EMG) and postmortem physical examinations of elasticity and load capacity of the different materials as well as histologic examinations after three and six months. A total of 89 animals survived and were subject to the analysis. There were no differences between the groups concerning growth and weight gain. The EMG showed normal function for the absorbable material and the transversus muscle. Only scanty physiologic waves were registered in the PTFE group. Load capacity measurements showed the lowest value of 4.71 N for the native diaphragm; all other materials had much higher values (17.66 N – 51.99 N) with a peak load capacity in the PTFE group. Measurements of elasticity displayed similar results. The native diaphragm had the lowest value (1516 N/m); much higher values were found in all the other materials tested (3905 N/m – 7654 N/m) with again peak values for PTFE. The differences of all materials compared to native diaphragm were statistically significant (p<0.05). The histologic examinations revealed strong foreign body reactions in the dura and PTFE groups. The absorbable bovine serosa had vanished three months postoperatively. Short-term absorbable bovine serosa tested successfully as a partial replacement of the diaphragm in this experimental study on rats. There may be additional indications for this material if a temperary replacement is intended.