The files include those on former Prime Ministers Jawaharlal Nehru, Indira Gandhi and Indo-Pak relations.
The old files are an important source of material for research and reference purposes.
"The Ministry of External Affairs has been making a steady progress in declassifying old records and making this accessible to the academic community.
"70,000 files were already declassified and transferred to National Archives of India," the ministry said in a statement.
In collaboration with National Archive of India these files have now been catalogued in a user-friendly, searchable format and the titles and file numbers have been uploaded on the public diplomacy website --www.Indiandiplomacy.In.
The website also provides information on the modalities of accessing the files at National Archives.
A further 22,000 files will soon be added to this list and efforts are on to expedite the process further, the Ministry said.