A household survey was conducted with a sample of 2,252 parents with adolescent children aged between 13 and 19 years from November 2009 to January 2010 in seven communities in Chilinh district, Hai Duong province. The survey aimed to fulfil two objectives, which are: 1) To describe the parental care for their adolescent children; and 2) To determine the relation between the parental care and adolescent pre-marital sex. Data about parental care were connected with socio-economic data from DSS-CHILILAB. It was also connected with pre-marital sex data from the overall study of adolescents in 2010 (AH1-round 2). The exploratory factor analysis and multivariate logistic regression model were used for analyzing data. Results: The proportions of parental care for their adolescents were high in all four aspects. Parental care, especially the awareness of their adolescents' peers and emotions, was the protective factor for adolescent pre-marital sexual intercourses. Recommendations: Parents need to care for their adolescents in order to mimimize the likelihood of their adolescents having pre-marital sex. Besides, the researchers and social organizations should promote parental care for adolescents.