"I'm perfectly healthy. I don't have cancer," the Republican presidential contender told reporters after reading "A Visit From St. Nicholas" to more than a dozen children at Hale House, a residence for needy children. More journalists than children were crammed into the tiny room.
Giuliani, who was treated for prostate cancer seven years ago, was briefly hospitalized last week in St. Louis after suffering what he described as a severe headache. He canceled some events but was back campaigning in New Hampshire over the weekend, declaring he was tested and given a clean bill of health.
The former New York City mayor reiterated that message on Monday, saying that his PSA level - a test for prostate cancer - was measured three weeks ago and was "zero or negligible." High levels can indicate cancer.
Giuliani said his doctor would issue a full report after the holidays.
"I knew I didn't have cancer," Giuliani said, "but I wanted to be sure."
Giuliani's bout with cancer led him to drop his campaign in 2000 for the U.S. Senate seat eventually won by.
Energetic and cheerful on Monday, Giuliani wore red socks and a red Christmas tie adorned with stockings. He paused frequently during the reading, asking the children questions and pointing to large colorful pictures of Santa and his reindeer.
Noting that Santa's nose and cheeks were red, Giuliani pinched his own nose and cheeks to illustrate the point, then let go with a big "Ho ho ho."
As the children, ages 2 to 5, began playing with their toys, Giuliani told them they were all "very important" and asked them what they wanted to be when they grew up.
One boy said he wanted to be a doctor, but none of the children - despite hints from the adults at the center - said they wanted to be president.
Giuliani has read the Christmas story - better known as "Twas the Night Before Christmas" - to children at the Hale House for 14 years. He promised that if he's elected president, he would still return to read the Clement Moore classic.