Congenital heart diseases are considered one of the most important causes of death in children at different ages. They are caused by improper development of the heart during pregnancy. A detailed structured questionnaire was prepared to determine the most important risk factors of congenital heart diseases. It was applied on 300 subjects: 100 have congenital cyanotic heart diseases, 100 have congenital acyanotic heart diseases and 100 have normal heart.Positive consanguinity, genetic diseases, advanced maternal age, maternal febrile illness during pregnancy; X-ray exposure and administration of vitamins and folic acid in the first trimester are the most highly significant risk factors