The first and foremost duty of an auditor is to give an opinion on the true and fairness of the financial statements of any entity.

But before giving an opinion, CAG has the additional responsibility to compile the accounts of the Union and of each state. He acquires these from the initial and subsidiary accounts rendered to the audit and accounts offices under his control by treasuries, offices or departments which are responsible for the keeping of such account.

After compiling the accounts, The CAG shall prepare, in each accounts, showing under the respective heads, the annual receipts and disbursements for the purpose of the Union, of each state and union Territory. Then he shall submit these accounts to the President or the Governor of a State or a Administrator of the Union Territory having a Legislative Assembly on or before the date prescribed to him by such authority.

Apart from these, he also provides information and advice to the Union and state governments to assist them in the preparation of annual financial statements if they ask for it.