Established in 1965, the Data Unit of the CSDS is an archive of social scientific survey data on political opinion, attitudes, and social and political behavior.  Outside Western Europe and North America, the CSDS Data Unit is probably the largest archive of data with more than nearly hundred data sets concerning wide range of social and political issues.

The Data Unit holds both survey data collected through various scientifically national and state level surveys and Aggregate data sets on all the Lok Sabha and State Assembly elections held in India till date. In recent years, the data unit has expanded to include survey datasets corresponding with other projects undertaken by Lokniti such as the State of Democracy in South Asia survey and The Youth Studies.