Cindy McCain says she will never make her tax returns public even if her husband wins the White House and she becomes the first lady.

"You know, my husband and I have been married 28 years and we have filed separate tax returns for 28 years. This is a privacy issue. My husband is the candidate," Cindy McCain, wife of Republican presidential nominee-in-waiting John McCain, said in an interview aired on NBC's "Today" on Thursday.

Asked if she would release her tax returns if she was first lady, Cindy McCain said: "No."

The Arizona senator released his tax return last month, reporting he had a total income of $405,409 in 2007 and paid $84,460 in federal income taxes. He files his return separately from his wife, an heiress to a Phoenix-based beer distributing company whose fortune is in the $100 million range.

Sen. McCain is routinely is ranked among the richest lawmakers in Congress, but he and his wife have kept their finances separate throughout their marriage. A prenuptial agreement left much of the family's assets in Cindy McCain's name.

Democratic National Committee Chairman Howard Dean said Cindy McCain's refusal to release her tax returns gives the appearance of a double standard on the part of her husband.

"What is John McCain trying to hide?" Dean said in a statement. "Throughout this campaign, he has acted like his own calls for openness and accountability apply to everyone but himself. Now he thinks he can bring that same double standard to the White House."

In response, Republican National Committee spokesman Danny Diaz said, "Howard Dean continues to lower the bar in this election."

Democrats Barack Obama and Hillary Rodham Clinton filed joint tax returns with their spouses and publicly released those returns.