Background: Congenital heart disease (CHD) is commonly seen in patients with Down syndrome (DS) and is closely associated with morbidity and mortality. Maternal age is an established risk factor for DS. Objectives: The aim of the present study is to analyze the incidence of CHD in Down syndrome and the effect of maternal age on this incidence and the type of CHD. Materials and Methods: Six hundred and thirty-one patients with DS who were admitted to pediatric cardiology department, between December 2014 and December 2018, were retrospectively analyzed. The detected CHDs were evaluated in association with maternal age. Results: Four hundred forty-five (70.5%) cases had one or more congenital heart defect. Two hundred and seven patients (32.8%) had isolated simple defect while the remaining had complex or associated multiple CHDs (n:238, 37.7%). Considering all patients, secundum ASD (42.1%) was the Original Research Article