Florence Nightingale's Crimean fever and chronic illness have intrigued historians for more than a century and a half. The purpose of this article is threefold: (a) to discuss the facts that point to the cause of Nightingale's Crimean fever as brucellosis, (b) to show that her debilitating illness for 32 years (1855-1887) was compatible with the specific form of chronic brucellosis, and (c) to present new evidence that she was still having severe symptoms in December 1887, when it was previously felt that she had no severe symptoms after 1870.