NSW Premier Mike Baird fell down the stairs at his home in Sydney in the middle of the night and has hurt his back.
Sydney Morning Herald reported that he has fractured his vertebra.
Mr Baird posted an X-ray of his fractured vertebra on his Facebook and Twitter accounts.
On his Facebook, he wrote: "Note to self: when fetching a glass of water late at night, don't walk down the stairs in your socks with the lights out."
He said the prognosis was a slow recovery, with no need for surgery.
"Yeah, I know… The punchlines for this pretty much write themselves… Knock yourselves out (I almost did!)"
Inspite of the injuring, Premier Baird is expected to be back at work on Tuesday.
