School officials and close friend Bobby Gleason said Gondrezick died Monday at St. Rose Hospital in Henderson, Nev., after apparent complications from a heart transplant that he received last September.
"From what the doctors told us, the body just rejected the heart," Gleason said. "Gondo never gave up. The heart did."
Gondrezick starred on the Rebels' Final Four team in 1977, and his jersey No. 25 was retired by the program in 1997. He ranks 16th on the school's career scoring list with 1,311 points, and his 831 rebounds rank ninth.
"He was only 6-foot-6. The hustle is what made him," said former UNLV coach Jerry Tarkanian. "He would dive on the floor. He would take charges. If they kept that stat, he would have led the nation in taking charges.
"He was a fierce competitor and a very loyal guy. I'm going to miss him so much."
Gondrezick played for the Knicks and Nuggets from 1977 to 1983, and later spent 17 years doing color commentary on UNLV basketball broadcasts.
Play-by-play announcer Jon Sandler said he was surprised Gondrezick returned to calling games last year, eight weeks after transplant surgery.
"The only person not shocked was him," Sandler said.
Gondrezick is survived by a daughter and two sons. A memorial service was scheduled for 11 a.m. Thursday at the Thomas & Mack Center at UNLV.