Background: Although ventricular septal defect (VSD) is the most common congenital heart disease, it is usually diagnosed late. The image of the disease is variable; sometimes it is so calm and silent that it can even be cured and improved spontaneously, and in some cases, if proper, timely and early treatment is not carried out, it would lead to irreparable complications even in early life , such as mortality. This study aimed to study, review and how to proceed with the diagnosis, treatment and follow-up of these patients. It is hoped that the results of the present study will be used to improve the patient's condition. Methods: This was a cross-sectional study carried out on 145 patients with VSD during 54 months in Isfahan. The required data collected at the time of definitive diagnosis by taking their history. Disease was identified by color Doppler echocardiography, cardiac catheterization, and angiography when necessary. Results: The average age of initial diagnosis of the disease was 17 months and the average age of final diagnosis was 44 months. The initial diagnosis was associated in 85% of cases with a heart murmur. In 27.5% of cases, VSD was associated with other cardiac abnormalities. Pulmonary arterial hypertension was observed in 16.5% of cases. Fifty-nine surgical procedures were performed on 40 patients. Conclusion: During routine and daily examination of infants, the likelihood of heart disease should be taken into account; Performing an echocardiogram and a cardiac consultation in suspected cases would allow early diagnosis and possibly rapid treatment. Proper monitoring of patients will provide optimal care and treatment services middle of paper......and ultimately the treatment of heart disease.3. Considering the possibility of additional cardiac abnormalities as well as pulmonary hypertension would provide optimal care and treatment services at the right time. References…Table 1: The type of VSD and additional cardiac abnormalities, pulmonary arterial hypertension (PAH), number and age of surgeries in the patients studied. type of VSD Number (percent) PAH No. (%) Surgery No. (%) Age of surgery (months) Single VSD 105 (72.5) 8 (7.6) 15 (14) 45 ± 22 VSD with supplement cardiac anomalies 40 (27.5) 16 (40) 19 (47.5) 37 ± 14 Patent ductus arteriosus 20 (50) 11 (55) 19 (95) 10 ± 3 Patent ductus arteriosus with coarctation aortic 6 (15) 5 (83) 5 (83 ) 10 ± 3Atrial perforation 5 (12.5) - 1 (20) 44 ± 29Pulmonary artery stenosis 9 (22.5) - -Bacterial endocarditis 1 (0. 7)Mortality 2 (1.4)