The incidence of congenital heart disease (CHD) at Siriraj Hospital for the year 2000 was 4.36 patients per 1,000 livebirths. Types of congenital heart diseases seen by the authors were VSD (18.3%), PDA (16.3%), ASD (16.3%), combined simple left to right shunt lesion (24.7%), tetralogy of Fallot (TF; 6%), D-TGA 2 per cent, other complex congenital heart 8 per cent. Overall 3 out of 1,000 livebirths will have congenital heart disease that will require immediate intervention including cardiac catheterization and surgical intervention. At the same period of time an average of 750 new cases of children were referred annually for evaluation and treatment of cardiac related problems. Reports of acquired heart disease such as acute rheumatic fever, myocarditis, Kawasaki's disease and arrhythmia problem were summarized here. The Division of Pediatric Cardiology performs both diagnostic and intervention cardiac catheterization in almost 310 children and adults with congenital heart disease yearly. Out of this 35 per cent had interventional procedures including balloon valvuloplasty, balloon angioplasty and stenting, device closure of atrial septal defect and patent ductus arteriosus and radiofrequecy ablation of abnormal conduction pathway. Major progress has been made in pediatric cardiac imaging over the past two decades. At Her Majesty's Cardiac Center, cardiac MRI has been used to evaluate patients with congenital heart disease since June 2000. There were 146 congenital heart disease patients who had cardiac MRI performed for the evaluation of anatomy, function, left to right shunt, and flow regurgitation quantification. CONCLUSIONS Pediatric Cardiology practice has evolved over the past decade and expanded from clinical practice to therapeutic intervention procedures.