The purpose of this study was to evaluate the knowledge about gestational diabetes mellitus (GDM), quality of life (QOL) and impact of counselling provided to the patients with GDM. With this view, a prospective, case-control study was conducted on October-2014 to March-2015 in the Department of Obstetrics and Gynaecology, Cosmopolitan Hospitals Pvt. Ltd, Thiruvananthapuram, Kerala, South India. The study includes 140 pregnant women in second trimester with GDM. The total study population was divided in to two groups of 70 members each. The group-1 was considered as control and 2 is considered as experimental group. A three month education course was provided to group-2 members during their antenatal visit. The education mainly focused on the information about the essence of GDM, complications of improper disease management and proper diet regimen. The education also covered the general concept of GDM self monitoring and the importance of active participation of patient in the treatment. The QOL and the knowledge of the participants were assessed in the beginning and the end of educational session with the help of semi structured questionnaire. The data collected was analyzed by using statistical package for the social sciences (SPSS) software. Analysis of data collected before and after counselling clearly indicated a significant improvement in the knowledge about GDM and QOL of participants belongs to group-2 comparing with group-1. Collectively, these results suggested that the educational approach is a necessary step for the better management of GDM and also future direction should focus on the earlier prediction and effective preventive measures before GDM development.