The medical records of 2283 patients with ventricular septal defect (VSD) were reviewed to determine spontaneous closure, left ventricular-to-right atrial shunt, subaortic ridge, and aortic valve prolapse. One thousand eight hundred and twenty-three patients had been followed 1 month to 26 years (median 4 years) by echocardiography. Most of 460 patients could not be followed due to transportation of the institution. VSD was perimembranous in 68.8% (1255), trabecular muscular in 21.7% (395), muscular outlet in 6% (109), muscular inlet in 2.6% (48), and doubly committed subarterial in 0.9% (16). Defect size was classified in 66.8% (1218) as small, in 15.7% (286) as moderate, and in 17.5% (319) as large. VSD closed spontaneously in 18.8% (343 of 1823 patients) by ages 40 days to 24.9 years (median, 1.8 years). One hundred fifty-seven of 1255 perimembranous defects (12.5%) and 167 of 395 trabecular muscular defects (42%) closed spontaneously (p < 0.001). Defect size became small in 306 (16.8%) of patients with VSD at a median of 2.5 years. Aneurysmal transformation was detected in 32.9% (600), left ventricular-to-right atrial shunt in 9.7% (176), subaortic ridge in 2.6% (48) of 1823 patients who were followed. In 381 (20.9%) of the 1823 patients, the VSD had been closed by a surgical or transcatheter technique. Surgery is required in one-fifth of patients with subaortic ridge or aortic valve prolapse. In conclusion, isolated VSDs are usually benign abnormalities that tend to shrink and close spontaneously.