The interest of the medical community in quinolones has not decreased despite more than ten years of continuous and growing use of these agents. The constant need for new anti microbials has produced a variety of newer quinolones termed as I, II, III, and IV generation. Nalidixic acid and other early quinolones had limited use due to poor pharmacokinetics, relatively narrow antimicrobial spectrum of activity, and frequent adverse effects. Extensive pharmacologic and clinical development of quinolone antimicrobial agents has resulted in improved antimicrobial activity, pharmacokinetic features, toxicity, and drug-drug interaction profiles. These attributes, coupled with their expanded spectrum and the immune enhancing phenomena of quinolones with a cyclopropyl moiety at position 1 of the quinolone ring suggest that the newer fluoroquinolones are so far the most ideal agents for the empirical treatment of many common infections. The above has made it desirable to review the status of these agents as revealed in published literature. The thrust of this review is on the structural development, pharmacological, haematological and immunological effects of quinolones. Recent patents filed are also discussed.