Klebsiella are well-recognized community and nosocomial pathogens responsible for septicemias, urinary tract infections, pneumonia, and soft tissue infections. The emergence of multi-drug resistant Klebsiella is becoming a global concern. Since fluoroquinolones are excellent antibiotics for clinical therapy of complicated infections, their consumptions have increased rapidly. Coincidental with the increased usage of fluoroquinolones, the incidences of drug resistance have increased, which highlights the need for understanding the molecular mechanisms of fluoroquinolone resistance. Alterations in targets and reduction of intracellular drug accumulation are two major mechanisms involved in fluoroquinolone resistance. This review focuses on the mechanisms of action of fluoroquinolones and molecular mechanisms of drug resistance, including known and proposed ones, and the discussion on clinical impact of multi-drug resistance in Klebsiella.