Rauzzini died at his home, 13 Gay Street, Bath, on April 8, 1810, in his sixtythird year. According to Mrs. Piozzi, Rauzzini did not own this house but rented it from Miss Wroughton. Evidently, he was in some financial distress at the time: Mrs. Piozzi writes that Rauzzini was forced to borrow ten guineas from her so that the rent could be paid. She records that he thanked her “almost with Tears” in his eyes. She suggests that Miss Wroughton could have done more for Rauzzini in his hour of need, and records that he died in considerable distress. Appearances may well have been more important to Miss Wroughton than reality. Mrs. Piozzi writes that “She wore Widow's Mourning on the Death of poor Rauzzini!!!”

The exact cause of his passing has not been established, although the European Magazine speaks of a “mortification, which began in his leg, and rapidly spread over his body.” Whether or not this was a thrombosis, leg injury, or ulcer that led to a blood infection is difficult to confirm at this late date. Moist gangrene is also associated with the term “mortification,” and the resulting spread of toxins may have been so rapid that no surgical options were viable. The effects of gout would seem less likely to be the cause of Rauzzini's sudden death. While his final illness was brief and unexpected, it is possible that his general health had been declining for some time. The strain of thirty years preparing the Bath concerts, dealing with the vagaries of temperamental soloists (Catalani's name comes quickly to mind), and facing the ever-pressing financial worries attendant to running the subscription concerts may have undermined his general health.

A comparison of the engraving by Samuel Freeman (ca. 1806) with the miniature portrait by Hutchinson (ca. 1790–95) reveals a significant physical change and decline. He would not have been considered young in 1810, but even by 1806 Rauzzini looks older than his years. His face is sunken, and has a haunted look. Mrs. Piozzi declared “Rauzzini but half alive” in her diary on September 14, 1806, after she had listed the passing of several family members and friends. He had suffered from colds and other illnesses in 1808 and had been too ill to conduct the concert of January 11, 1809.