Jill Fayers, 45, took money from the safe at the Skiddaw Walk mental health unit in Northampton to win cash at the casino.
Fayers grabbed petty cash and more than £100 belonging to 'client A' during a night shift on March 16, 2005.
The mother-o
f-two then borrowed £400 from her boyfriend's sister so she could put it back in the safe, the Nursing and Midwifery Council heard.
The nurse, of Towcester, Northamptonshire, denied taking the money without authority and leaving unqualified nursing assistant, Mary Sheppard, alone for up to six hours that night.
She branded the allegations a 'load of rubbish' and said the case against her only came to light when she was about to accuse boss Duncan Herring of sexual harassment.
But an NMC panel ruled she was guilty of the charges and found her actions amounted to misconduct.
Panel chairman Stephen Barker said he was satisfied a caution order for the maximum period of five years was an appropriate sanction.
He said: "Ms Fayers' actions on that night were a grave breach of her professional duty of care and her position of trust as a registered nurse.
"Although the panel recognise that the monies used were repaid in full on that night, there is no doubt her actions were deliberate.
"Until today she has never really faced up to the reality of what she did.
"We have heard she found herself in serious financial difficulties at the time and it may well be that her reckless and grossly unprofessional conduct arose out of a genuine sense of desperation on her part.
"She has assured us that she has not been to a casino since the date of these allegations. We hope that is the case.
"In all the circumstances we are satisfied that the order we are making will provide an adequate safeguard for the purposes of public protection, at the same time as giving Ms Fayers the opportunity to return to the profession which she described with some passion before us as having been her true vocation."
Fayers, who represented herself at the London hearing today, can now continue her 23-year career in nursing after she completes a retraining programme.
