My whip has been restored with no conditions other than those which apply to any party MP. Work continues as normal
There had been widespread speculation that Mid Bedfordshire MP had been contemplating a move to UKIP.
However, it is understood the Ukip issue did not come up at her meeting with Sir George this afternoon, which was described as "convivial".
Ms Dorries said: "I am delighted. It is long overdue."
Nadine Dorries has had the Conservative whip restored after apologising for taking part without permission in ITV's I'm A Celebrity...Get Me Out Of Here!
A Conservative Party spokesman said current chief Sir George Young had restored the whip "with immediate effect" after a meeting this afternoon.
Nadine has apologised to the Chief Whip for absenting herself from her parliamentary duties without permission and has given assurances to the Whips Office that she will follow the same procedure as other Conservative Members of Parliament before going away when the House is sitting.
Nadine Dorries had hinted yesterday that the whip might be reinstated on her Twitter account.
She posted links to a Huffington Post story which suggested senior Tories felt the suspension had gone on too long.
She also posted a link to a Telegraph story hinting at her plans to appeal against the suspension.
just spoken to @nadinedorriesmp who confirms she is back in the con parliamentary party, Mid Beds Con Assn say decision long overdue
ITV News Anglia Political Correspondent Emma Hutchinson has spoken to Nadine Dorries and has confirmed she has had the whip reinstated.
There had been some concerns the Mid Bedfordshire MP was being courted by UKIP.
Mid Bedfordshire MP Nadine Dorries has had the whip restored today, it is being reported.
The controversial Conservative had the whip taken away - effectively excluded from the Tory Parliamentary party - after she decided to take part in I'm a Celebrity Get Me Out of Here.
Nadine Dorries has vowed to 'go after' the Independent Parliamentary Standards Authority after it was revealed an investigation into her expenses claim was launched.
The Independent Parliamentary Standards Authority said they had reason to believe Ms Dorries may have been paid travel and accommodation costs she was not entitled to.
A defiant Ms Dorries vowed to "go after" Ipsa, claiming the expenses body had simply targeted a high-profile MP to justify its funding.
She insisted she was "totally relaxed" about the allegations, saying they were completely unfounded.
They need a high-profile MP to go after to justify their millions in funding. Well I'm going to go after them. All they want to do is get attention to show Ipsa is doing its job.
Mid-Bedfordshire MP Nadine Dorries is facing an investigation into her expenses claim by a parliamentary watchdog.
The Independent Parliamentary Standards Authority's Peter Davis said he had reason to believe Ms Dorries may have been paid travel and accommodation costs she was not entitled to.
"An investigation will be conducted into claims submitted under the following areas of the third and fourth editions of the MPs' scheme of business costs and expense - accommodation expenditure, travel and subsistence," he said in a statement.
The Independent Parliamentary Standards Authority said today it is to investigate expenses claims submitted by Mid-Bedfordshire MP Nadine Dorries.