Introduction: Quinolones are one of the most favourable antimicrobial class for the treatment of various infectious diseases. Their side effects and toxicity profile have been established years ago. Multiple studies reported dysglycemic events occurring in diabetic patients admitted to the ICU taking fluoroquinolones. The aim of this study is to determine if there is indeed a relation between fluoroquinolones and dysglycemia. Methods and Materials: A retrospective observational study targeting the ICU patients who were administered levofloxacin, ciprofloxacin, and moxifloxacin. This study was performed during the period from April 2019 to September 2019 (6 months) in 5 different hospitals in Alexandria, Egypt. 350 patients' ICU files were chosen randomly, then a total of 68 diabetic ICU admitted patients receiving broad-spectrum fluoroquinolones for more than 2 days were included in the study. Results: From 68 patients who recruited in our study, 15 patients take fluoroquinolone with no need and they suffer from change in their blood glucose level without any additional benefit. The most misused fluoroquinolone was Levofloxacin, as 73.3% of patients with main diagnosis non-infectious treated with Levofloxacin, and 20% among them suffered from decreased blood glucose level where 13.3 % had significant increase of their blood sugar level. Conclusion: Dysglycemia caused by fluoroquinolones is an important issue of clinical significance and must be addressed and managed. Dysglycemia occurs by varying degrees and differ between different agents of fluoroquinolones. The effect is more pronounced in diabetics and patients with renal impairment which warrant attention and immediate management. Fluoroquinolone misuse is also another important issue to be addressed as it contributes to increased antimicrobial resistance and exposes the patients to unnecessary side effects some of which might need immediate intervention. Further investigations related to fluoroquinolones prescribing and monitoring is needed to get a better understanding of this existing problem.