The discussion about the corporate sustainability issues getting more importance in recent days. The stock markets around the world also are affected with this subject of discussion. Investors as well as the companies theirselves are considering sustainability concepts during taking their investment decision strategies. Many index providers launched different ’Sustainable stock’ indices around the world to recognise these new investment decision choices. But do the investors actually care about the sustainability during their investment choices? The purpose of the study was to explore the answer of this unsolved question. Towards achieving the goal the study has been conducted to explore the relationships between the announcement of the ’Dow Jones sustainability Index Emerging Markets’ and the market reactions. Though there were some efforts, which were done to understand the patterns of the relationships between these two variables in developed markets, but no such study has been conducted in case of emerging markets. An event study was conducted to find out the answer of the research question. Five years panel data from 2015 to 2019 of the listed companies on the ’Dow Jones sustainability Index Emerging Markets’ were considered as the study sample to analyse the market reactions for the announcement of this index of this study period. The findings of the study did not recieve any significant influences of the announcement of inclusion, exclusion and continuation events on the stock market return at that study period. That means the investors in the emerging markets did not care about the sustainable performance of the listed companies during their investment decisions. But this study provide a deep insight about the future trend of sustainable investment, as the announcement events had some non-significant influences on the return trend. The results of the study indicate that investors are getting aware of the corporate sustainable performances day by day. Hopefully these insights give us the opportunity to anticipate that the investors will consider the sustainability issues more in their investment decision making process in the future.