The writer of the Harry Potter books, who lives in Edinburgh, has publicly backed the Better Together campaign.
Explaining her decision on her website, Ms Rowling said there was a "denial of risks" within the "Yes" campaign.
She also said there was a "fringe of nationalists who like to demonise anyone who is not blindly and unquestionably pro-independence".
She added: "My hesitance at embracing independence has nothing to do with lack of belief in Scotland's remarkable people or its achievements. The simple truth is that Scotland is subject to the same 21st century pressures as the rest of the world. It must compete in the same global markets, defend itself from the same threats and navigate what still feels like a fragile economic recovery."
"The more I listen to the 'Yes' campaign, the more I worry about its minimisation and even denial of risks. Whenever the big issues are raised - our heavy reliance on oil revenue if we become independent, what currency we'll use, whether we'll get back into the EU - reasonable questions are drowned out by accusations of 'scaremongering'".
Full story: http://www.bbc.co.uk/news/uk-scotland-scotland-politics-27793967