This study was designed to determine the clinical status, cause of death, and effects of pulmonary vascular disease and conduction abnormalities 30 to 35 years after surgery in 296 consecutive surviving patients of closure of ventricular septal defect. Of the 296 patients, current status was determined by contact with patient and physician in 290 cases, with 6 (2%) lost to follow-up (7,912 patient years are included). Cardiac catheterization after surgery in 168 patients showed complete closure of the defect in 80%. Death occurred in 59 patients (20%), with higher mortality rates in those operated on after the age of 5 years, those with pulmonary vascular resistance greater than 7 units (51%), and those with complete heart block (78%). Of 37 patients with transient heart block after surgery, 8 (22%) have died (3 pulmonary vascular disease, 2 sudden death, 2 unknown causes and 1 complete heart block). Twenty other patients had a dysarrhythmia after surgery, and none of these died. Nine episodes of endocarditis occurred (11.4/10,000 patient years). Nine of 296 (3%) offspring had cardiac malformation. Most patients are in New York Heart Association class I, 57% attended college and 15% received an advanced degree. The data show good results for this group of patients operated on during an early era (1954 to 1960) of open cardiac surgery. They support the current trend toward operation in patients with ventricular septal defects at an early age and with low pulmonary vascular resistance.