Third All India Census of Small Scale Industries (SSI) was conducted with reference year 2001-02. The Census covered both Registered and Unregistered Sectors for the first time. The census adopted different methodology for Registered and Unregistered Sectors. While complete enumeration of enterprises was adopted in Registered Sector, Sample Survey was resorted to in Unregistered Sector. Based on the data sets of Third All India Census of SSI one report was published. The report could be accessed at link as noted below:

The latest census conducted on Micro, Small and Medium Enterprises (MSME) is the Fourth All India Census of MSME 2006-07. The data was collected till 2009, results of which were published in 2011-12. The census adopted different methodology for Registered and Unregistered Sectors. While complete enumeration of enterprises was adopted in Registered Sector, Sample Survey was resorted to in Unregistered Sector. However, for activities under Wholesale/Retail trade, legal, educational & social services, hotel & restaurants, transports and storage & warehousing (except cold storage), which were excluded from the coverage of Fourth All India Census of MSME 2006-07, data was extracted from Economic Census 2005 conducted by Central Statistics Office, Ministry of Statistics and Programme Implementation for finalising the report on MSME Sector. Based on the above data sets, three reports were published which are as noted below: