 Ciprofloxacin is a commonly prescribed antibiotic used to treat various bacterial infections. However, it has been associated with serious side effects such as acute renal failure due to interstitial nephritis. In this case report, an elderly patient was diagnosed with oliguric acute kidney injury, aka following treatment with both oral and intravenous Ciprofloxacin over a 48-hour period. The patient's urinary sediment revealed the presence of Ciprofloxacin crystals which were found to be responsible for the development of AKI by causing intratubular precipitation in alkaline urine. This case highlights the importance of recognizing the potential risk of developing AKI from Ciprofloxacin use and emphasizes the need for early detection and appropriate management of the condition. This article was authored by Mabub Khan, Luis M. Ortega, Nazreen Bagwan and others.