Early marriage has many problems for girls in the world in general and in developing countries in particular. It results in the health, and socio-economic aspects of girls; mistreatment, marginalization and denying basic human rights of girls. Early marriage also limits many girls’ mobility, self-esteem, ability to seek profitable employment, and household decision-making power, and increases their vulnerability to violence. Each of these factors has a potent effect on a girls’ ability to access healthcare, compromising not only her health but that of her children, and not being competent in economic and social affairs. This paper aims to examine and investigate the prevalence of early marriage in the study area (Nayagarh District, Odisha); identify the causal factors of early marriage in the study area, and examine its associated problems that its impact on the health and socio-economic condition of girls. In Nayagarh district, children marry early due to different reasons. Among the identified factors some are as a matter of their tribal tradition, fear of premarital sex and pregnancy, parents’ interest in following the consent of relatives, afraid of losing a financially sound bridegroom etc. The low economic status of parents and lack of knowledge are the main causal factors of early marriage in the area. The main consequences of early marriage identified in the study area are girls’ college dropout, marriage instability, early pregnancy, maternal mortality, and increased number of children.