The newest (third generation) fluoroquinolones are potentially useful agents in the management of community-acquired respiratory tract infections. This is mainly due to their increased activity against Streptococcuspneumoniae, a pathogen poorly susceptible to the second-generation compounds, and playing a major role in upper and lower respiratory tract infections. Also, their spectrum includes the other main pathogens involved in those infections, comprising Haemophilus influenzae and intracellular agents, against which the newest fluoroquinolones exhibit a similar activity to that of the previous compounds. The pharmacokinetic and pharmacodynamic properties of the newest quinolones make them suitable for effective therapy of lower respiratory tract infections. However, careful attention should be paid to the dose and dosing regimen of each compound in clinical usage in order to select the most adapted drug. In clinical trials, the fluoroquinolones have been shown to be at least as effective as the comparators in the treatment of community-acquired pneumonia, acute exacerbations of chronic bronchitis (AECB) or sinusitis, including documented pneumococcal infections. Their tolerance is generally considered to be good. The main question regarding the fluoroquinolones in the treatment of community-acquired respiratory tract infections is their role as first-line agents used in single drug therapy. Cost-effectiveness studies are needed to define this role further. Identification of subpopulations of patients at risk of being infected by penicillin-resistant pneumococci or Gram-negative bacilli who could benefit from a fluoroquinolone could be useful. Also, it must be considered that a large use of fluoroquinolones as first-line agents in very common infections such as AECB or sinusitis could contribute to the selection of bacteria, including S. pneumoniae, resistant to this class of antibiotics. Careful control of fluoroquinolone usage and development of bacterial resistance is of great importance.