Hypoplastic left heart syndrome (HLHS) is a congenital heart defect (CHD) in which left side of the heart is severely underdeveloped. To better understand this unique physiology, a computational model of the hypoplastic heart was constructed on the basis of compartmental analysis. Lumped parameter model of HLHS is developed based on the electrical circuit analogy. Model is made up of three parts: hypoplastic heart, pulmonary circulation and systemic circulation. Plots of blood pressure and flow for various parts of body show great match between predicted values and what we expected for the case of HLHS babies. Influence of patent ductus arteriosus (PDA) and ASD resistances on cardiac output and pulmonary to systemic flow was also studied. Results show that by increasing the PDA resistance causes more flow to pulmonary compartments and so the ratio increases. Blood flow increases by decreasing of pulmonary artery resistant. Increasing the PDA resistance causes decrease the cardiac output because of more resistance against blood occurs. Saturation increases by decreasing of pulmonary artery resistant.