Christensen died during surgery at a hospital in Salt Lake City, The Salt Lake Tribune reported. He had liver disease and other illnesses for several years, the report said.
He was voted to the Pro Bowl after each season 1983-87. In 1983 and '85 he led the NFL in receiving. Christensen was on the winning team in Super Bowl XV and Super Bowl XVIII.
"Todd was an excellent football player and was prolific in the passing game," former Raiders Coach Tom Flores said. "He was a hybrid tight end, an H-back before it became a football term. ... He then helped us win Super Bowls.
"I remember Todd as always using big words and quoting famous authors and poets. He was comical at times because no one knew what he was talking about. I hadn't seen much of him lately but miss the fun, great times we all shared as a Raider family."
Christensen was a running back at Brigham Young University 1974-77 and led the team in rushing three seasons. He was inducted into the school Hall of Fame in 1992.
The Dallas Cowboys selected him in the second round of the 1978 draft. Christensen was injured before the 1978 season and didn't play for the Dallas, which released him in 1979. He was claimed off waivers by the New York Giants but lasted only one game with the Giants. The Raiders signed him in 1979 and he switched to tight end.
He went on to play 136 games for Oakland, catching 461 passes for 5,872 yards and 41 touchdowns.