After the first infection with Coxiella burnetii, chronic Q fever usually develops within 2 years. Researchers looked at the time between an acute Q fever and a diagnosis of a chronic illness, as well as the factors that contribute to a longer delay and the long-term outcomes. Patients with chronic Q fever from 45 hospitals were included in the study from 2007 to 2018. The time between acute and chronic infection was calculated in patients with a known day of initial symptoms and/or serological confirmation of acute Q fever. Two researchers investigated chronic Q fever-related morbidity and mortality using specified criteria. In all, 313 (60.3%) confirmed chronic Q fever patients, 81 (15.6%) probable chronic Q fever patients, and 125 (24.1%) possible chronic Q fever patients were found. In 200 patients, the date of acute Q fever was known: 45 (22.5%) had an interval of more than 2 years, with the most significant gap being 9.2 years after a 2-year gap, patients who had serological follow-up after acute Q fever were diagnosed less frequently (odds ratio, 0.26; 95% confidence range, 0.12–0.54). In 216 patients, problems from chronic Q fever occurred (41.6%). Chronic Q fever-related death was seen in 83 (26.5%) of confirmed chronic Q fever patients and 3 (3.7%) of suspected chronic Q fever patients. Chronic Q fever is still being identified 8 years after a significant outbreak, and mortality is still occurring. The time between an acute case of Q fever and a diagnosis of a chronic infection might be as long as nine years. Even many years after an outbreak of acute Q fever sickness, clinicians should perform microbiological testing for chronic Q fever.