A technical and economic evaluation of the plant has shown it can operate for a further seven years.
The power station was initially scheduled to be closed in 2011, but this was then extended until 2016.
While the Scottish government is opposed to the construction of new nuclear power stations it is "perfectly open" to continuing operations at Hunterston and its sister station at Torness in East Lothian.
A spokesman said: "We have consistently made it clear that nuclear energy will be phased out in Scotland over time, with no new nuclear build taking place in Scotland.
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"But we have also consistently made clear that this does not preclude extending the operating life of Scotland's existing nuclear stations to help maintain security of supply over the next decade while the transition to renewables and cleaner thermal generation takes place."
The plant currently employs over 700 people and generates enough electricity to supply almost half of Scotland's homes.
Hunterston Station director Colin Weir said: "This is great news for Hunterston B, Ayrshire and for Scotland.
"Today's announcement is also recognition by EDF Energy of the professionalism of everyone at Hunterston B, which has been supplying electricity to Scotland for more than 36 years."
EDF Energy says the financial benefits of the station to the local economy are £40m a year.
It says Hunterston B has produced about 250 terawatt hours (TWh) since operations began in 1976, while at the same time avoiding at least 160m tonnes of CO2 from entering the atmosphere.
But Patrick Harvie MSP, Scottish Green Party co-convener, said: " This extension shows how light touch regulation is failing us and the Scottish Government shouldn't just wave it through.
"The Scottish Parliament has voted against new nuclear, and it's clear our renewables targets are achievable. Why on earth would we allow EDF to increase our toxic waste legacy and continue the risks of running a plant built in the 60s?"
(IT/GK)
