Etiology of congenital heart defects are complex and possibly lie within the interaction of environmental exposures and inherited factors. Exploration of the contribution of environmental risk factors that are potentially modifiable impeded the prevention of CHDs. This study was conducted to evaluate the environmental risk factors of CHD. It was a case control study, conducted from July 2018 to June 2019 in Paediatric Cardiology department of Dhaka Shishu (Children) Hospital, Bangladesh. Parents of the children with CHDs visiting the out-patient department were considered as case. Control was taken from parents of the children not having congenital heart disease. Data were collected by face-to-face interview using a structured questionnaire containing all the variables of interest and analyzed by using SPSS version 21.0. Majority of the respondents were from rural area (86.9% and 80.0% in case and control group respectively) and CHD was found significantly higher in rural population (p<0.05). Consanguinity was present in 8.9% in case group and CHD was found significantly higher among children born to consanguineous parents (p<0.05). Most of the mother (65.4%) had completed primary level of education however 11.9% mother was illiterate in case group. CHD was found significantly higher among illiterate mothers (p<0.05). Most of the respondents belonged to lower and lower-middle class family (83.1% and 75.7% in case and control group respectively) and CHD was found significantly higher among them (p<0.05). Mothers exposed to passive smoking and in stress during pregnancy period, CHD was significantly higher (p<0.05). No significant association was found between maternal drug use and infection during pregnancy period with CHD (p<0.05). Maternal illiteracy, residing in rural areas, low and lower- middle class socioeconomic status, consanguineous marriage, exposed to passive smoking and stress during pregnancy period have been significantly associated with CHDs.