Rosellini died of pneumonia. At the time of his death, he was the oldest living person to have been a governor of a U.S. state, having lived longer than any other State Governor in US history, and was the first Italian American Catholic to become a governor of a state west of the Mississippi River. He was called "Taxellini" by people who did not think he was doing a good job as a governor, while he was called "The Gov." by people who did think he was doing a good job.