Blatnick died of complications from heart surgery, USA Wrestling said on its website, citing a report from television station WNYT in Albany, N.Y. Officials at Ellis Hospital in Schenectady confirmed that he died there of heart failure.
Blatnick was a high school state champion in suburban Albany in the mid-1970s and a two-time Division II national champion and three-time Division II All-American at Springfield College in Massachusetts.
He qualified for the U.S. Olympic team and was a member of the 1980 squad that didn't compete because the U.S. boycotted that year's games in Moscow.
In 1982, he was diagnosed with Hodgkin's disease, or cancer of the lymph system. After radiation treatment and the removal of his spleen, the disease went into remission, allowing Blatnick to compete at the 1984 Olympics.
He had switched from freestyle to Greco-Roman wrestling, which allows no holds below the hips. At 248 pounds, he competed as a super heavyweight during the contest, held at the Anaheim Convention Center.
Inspired by the memory of his brother, David, who died in a 1977 motorcycle accident, Blatnick defeated 275-pound Tomas Johansson of Sweden in the final to win gold, afterward falling to his knees and crying.
"I'm a happy dude," the 27-year-old Blatnick said through tears in a TV interview at the side of the mat.
Blatnick and his 1984 teammate Steve Fraser became the first Americans to win Olympic gold in Greco-Roman wrestling, and Blatnick carried the U.S. flag at the closing ceremony at the Coliseum.
A year later he suffered a cancer relapse and overcame it again. By 1988 he had retired from competition.
Born July 26, 1957, in Schenectady, Blatnick had spent the last several years volunteering as a high school wrestling coach in upstate New York.
A three-time national champion in Greco-Roman, he was inducted into the National Wrestling Hall of Fame in 1999, served on USA Wrestling's board and worked as a television commentator and as a motivational speaker.
Information on survivors was not immediately available.