Corporations have come to the realization that numerous benefits can be derived by being socially responsible in the societies they operate. Presently, the argument is not just about being a good corporate citizen but the ability of a business to communicate its social contributions to the stakeholders. Therefore, the present study examines the extent of corporate social responsibility disclosure (CSRD) practices by NIFTY 100 companies in the voluntary period of CSRD and the period after the implementation of Section-135 of the Companies Act, 2013. The annual reports of companies are content analyzed using a CSRD measurement index to calculate disclosure score under six themes of corporate social responsibility, namely community development, human resource, environmental activities, development of rural areas, product and customer relation, and fair business. The percentage of companies making CSRD has been increasing over the period of study. In both periods, environmental activities is the most disclosed CSRD theme followed by human resource.Moreover, the results have shown a significant difference in the CSRD practices of sectors. Overall, companies operating in more sensitive sectors and high visibility sectors engage more in CSRD practices. Lastly, the results also indicate that companies have focused on different CSR themes depending on their sector type.