An additional 44 percent are undecided or don't know enough about the first lady to hold an opinion.
Michelle Obama's rating is more positive than those of her predecessors at this early stage in her time in the White House.
Laura Bush's favorable rating at the beginning of her husband's presidency was 30 percent, while Hillary Clinton's favorable rating was 44 percent, Barbara Bush's was 34 percent and Nancy Reagan's was 28 percent.
Mrs. Clinton and Mrs. Reagan also had double digit disapproval ratings at this point, with 16 percent disapproving of Mrs. Clinton and 10 percent disapproving of Mrs. Reagan. Disapproval ratings for Laura and Barbara Bush were just 3 percent.
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This poll was conducted among a random sample of 1,112 adults nationwide, interviewed by telephone February 18-22 2009. Phone numbers were dialed from RDD samples of both standard land-lines and cell phones. The error due to sampling for results based on the entire sample could be plus or minus three percentage points. The error for subgroups is higher. This poll release conforms to the Standards of Disclosure of the National Council on Public Polls.