Objective: To assess frequency of cardiac defects among children from birth to 12 years of age on echocardiography basis in a teaching hospital of Khyber Pakhtunkhwa Pakistan. Methodology: This prospective study was conducted at pediatric unit of king Abdullah teaching hospital Mansehra Khyber Pakhtunkhwa (Pakistan) for one year from 1st January 2008 to 31st December 2008. A sample of 100 patients (<12 years age) were selected. The cardiologists performed echocardiography by Pediatric Transthoracic echo probe; 2-D color Doppler, Acuson CV-70 & Niemo-30 echocardiography machines. All consecutive patients with suspected cardiac problems on the basis of history and examination and confirmed by echo were included in the study. Variables included were: A-Muscular plus Vascular defects; B-Valvular defects; C Pericardial effusion; D- Dextrocardia and E-Congestive cardiac failure. History of children for cynosis, breathlessness, cyanotic spells, sore throat followed by joint pains; history of mothers for drug intake (antihypertensive, antipyretic, anti-emetic, hypoglycemic) as well as chronic diseases (diabetes mellitus, hypertension, anemia) during pregnancy were surveyed. Parity of mothers, their cousin marriages, and family socio-economic status was also inquired. The results were tabulated, analyzed and finally subjected to suitable test of significant (SR of proportion) to find out statistical significant if any. Results: Out of 100 patients, It was found that 53 (53%) were suffering from Cardiac muscular and Vascular defects which includes, Ventricular Septal Defect (VSD) 28.30%, Tetralogy of fallot,s (TOF) 24.52%, cardiomyopathies 24.52%, Patent Ductus Arteriosus (PDA) 15.09% and Atrial Septal Defect (ASD) 7.54%, and 42 (42%) Valvular defects which includes mitral valve defect 23.80%, combined aortic and mitral valve lesion 50%, aortic valve defect 19.05%, tricuspid valve defect 4.76% and pulmonary valve defect 2.38%. 1 (1%) Pericardial effusion, 1 (1%) Dextrocardia and 3 (3%) from Congestive Cardiac Failure. According to age, 36 (36%) were from birth to 3 years of age and 34 (34%) from 10 to 12 years. There was history of Rheumatic fever among 32 (32%) children. There were 72 (72%) children from lower socio-economic class and 53 (53%) parents had history of cousin marriages. Conclusion: The most common cardiac muscular defects in this study are: Ventricular Septal Defect (VSD) followed by Tetralogy of fallot,s (TOF), cardiomyopathies, Patent Ductus Arteriosus (PDA) and Atrial Septal Defect (ASD), and the most common valvular defect is mitral valve defect followed by combined aortic and mitral valve lesion, aortic valve defect, tricuspid valve defect and pulmonary valve defect.