The account will initially launch in a small number of regional Post Office branches before being rolled-out more widely in 2014.
The organisation said the new account would aim to be simple, transparent and offer good value for money.
The move will make the Post Office one of the largest providers of financial services on the High Street. It already has almost three million customers and a savings book of £17bn.
With more than 11,500 branches, this is more than all the UK banks combined. It would also help those living in rural areas with limited access to bank branches.
Nick Kennett, director of financial services at the Post Office, said: "This is exciting news for the Post Office and we are absolutely delighted to announce that we are going to launch a current account.
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"We've carried out extensive research into the current account market and the findings tell us that customers want simplicity, transparency and good value for money.
"The Post Office is undertaking a significant transformation, providing more and more essential services to our customers across mail, government and financial services. The introduction of the current account is a further statement to this ambition."
Commenting on the move, Dr Peter Hahn from Cass Business School said: "With most people having access to free in-credit current accounts today and transactions continuning to migrate online, it is hard to see how the Post Office is going to differntiate itself in an already crowded field."

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