BACKGROUND Prosthetic or pericardial patches used for the closure of atrial septal defects are associated with infrequent but definite problems. As an alternative, we used a right atrial free-wall patch in 12 patients, 7-54 years of age. RESULTS The presence of a large secundum atrial septal defect (n=2). associated mitral valve regurgitation (n=7), primum atrial septal defect (n=2) and sinus venosus defect (n=1) necessitated the use of a patch. The mitral valve was repaired in 9 patients (including 2 with a primum defect). One patient with a primum defect who was in congestive heart failure preoperatively died after 3 weeks due to refractory ventricular fibrillation. The remaining patients were discharged 5 to 7 days post procedure. No flow was detected across the septal patch on predischarge echocardiography. One patient underwent reoperation for failed mitral valve repair one month postprocedure. At reoperation, the patch was found to be intact with normal texture and without any suture dehiscence. Histopathological examination of the explanted patch revealed viable endothellum and subendothelial muscle on both surfaces of the patch. Follow-up ranged from 6 to 36 months. Echocardiography performed after 6 to 32 months post procedure showed an intact patch with no residual defect. All the patients are in sinus rhythm. Holter monitoring performed in 6 patients was normal in all of them. Electrophysiological study was performed in 2 patients using a mapping catheter 4 and 6 months post-procedure, respectively, and recorded normal atrial potentials from the site of the patch. CONCLUSIONS The use of an autologous free right atrial wall as a patch for atrial septal defect closure is a viable option.