Obama, the Times said, was given the bracelet by Tracy Jopek of Wisconsin, at a rally on Friday night. He was still wearing it on Saturday as he campaigned across the state before Tuesday's primary.
The bracelet belonged to Sergeant Ryan David Jopek, and the date of the 20-year-old's death in Iraq -- August 2, 2006 -- is engraved on it.
''All gave some -- He gave all,'' the bracelet says.
The paper says that Obama told the Green Bay audience, ''She gave me this wristband, which I'm very grateful for.'' The presidential candidate halted and lowered his voice from his normally upbeat presentation.
''I meet mothers and family members all over the country who are still mourning their children but are also thinking about the young men and women who are still over there and wondering when it will end,'' Obama reportedly told the audience.
Obama has kept the bracelet, a black metal band with silver lettering, away from reporters, a campaign staffer told the paper.
During their brief meeting with the Illinois senator, Jopek and her daughter showed him a picture of a smiling Ryan dressed for battle, the New York Times reported.
Jopek, a Democrat who will vote for Obama in Wisconsin's primary on Tuesday, has been against the war from the start, the paper said.
''And it's not over for us until this war is over. I just don't want any more soldiers to die in vain for something that we can't solve,'' she told the paper.
Jopek, a self confessed political junkie, told the New York Times that she had noticed Republican presidential candidate John McCain wearing a similar bracelet.
McCain, the Arizona senator, received the bracelet from the mother of Corporal Matthew Stanley, who was also killed in Iraq, and he has been wearing it ever since.
Image: Democratic presidential candidate Senator Barack Obama sports the bracelet given to him by Tracy Jopek, mother of Sergeant Ryan David Jopek, during the Democratic Party Founders Day Dinner at Milwaukee, Wisconsin. Photograph: Scott Olson/Getty Images.