The Conservative MP confirmed she was self-isolating after testing positive, while officials were working to identify how she came into contact with the virus.
The Times reported that she had met hundreds of people in parliament in the past week and attended a Downing Street reception with Boris Johnson.
In a statement on Tuesday evening, Ms Dorries said: "I can confirm I have tested positive for Coronavirus.
"As soon as I was informed I took all the advised precautions and have been self isolating at home.
"Public Health England has started detailed contact tracing and the department and my parliamentary office are closely following their advice.
"I would like to thank PHE and the wonderful NHS staff who have provided me with advice and support."
Health Secretary Matt Hancock said he was "really sorry" to hear she had contracted the virus.
"She has done the right thing by self isolating at home, and both NHS and PHE staff have been brilliant. We all wish her well as she recovers," he added.
Ms Dorries tweeted: "Thanks for so many good wishes.
“It's been pretty rubbish but I hope I'm over the worst of it now. More worried about my 84yo mum who is staying with me and began with the cough today. She is being tested tomorrow. Keep safe and keep washing those hands, everyone."