The aim of this study was to review the use of fluoroquinolone (FQ) drugs in a teaching hospital and to bring to light the factors associated with FQ misuse. A prospective observational study of FQ prescriptions was conducted in a 2,200-bed teaching hospital. Every hospitalized patient receiving a FQ drug during the 3-week survey period was included. A questionnaire was filled out using medical records and face-to-face interviews with FQ prescribers. An infectious diseases specialist reviewed the questionnaires and analyzed FQ therapy according to local guidelines for FQ prescription. Among the group of 174 patients included, FQ therapy was inappropriate in 88 cases (50.6%; 95% CI 43-58) for the following reasons: inappropriate clinical setting, 43; non-first-line recommendation, 24; inappropriate choice of FQ agent, 9; and inappropriate combination of FQs, 12. FQ prescriptions did not comply with prescription rules in 45 cases (25.9%; 95% CI 20-33). Appropriateness and compliance overlapped for 17 of these 45 patients who received an inappropriate FQ course that did not comply with prescription rules. Finally, FQ therapy was misused for 116 of the 174 patients (66.6%; 95% CI 59-74). Characteristics linked with FQ misuse were hospitalization in surgical wards (p = 0.03), intravenous therapy (p < 0.01), and presumptive therapy (p = 0.05). The FQ misuse rate progressively decreased during the survey period (p = 0.04). FQ misuse was a common phenomenon in the teaching hospital studied. The significant improvement in FQ prescribing practices observed during the study period demonstrates that frequent review of antibiotic use with prescribers is warranted.