The activity of moxifloxacin was assessed against 1269 isolates of Streptococcus pneumoniae, comprising 462 isolates referred from UK hospitals, primarily for confirmation of resistance to first line agents, and 807 isolates from an enhanced surveillance of invasive infections. Resistance rates to penicillin, erythromycin, tetracycline and chloramphenicol were 88.7% (32.6% intermediate and 56.1% fully resistant), 50, 48 and 22.7%, respectively, for the former, and 8.0 (4.5% intermediate and 3.5% fully resistant), 14.7, 9.0 and 0.6% for the latter. Ninety-four per cent of the referred isolates and 99% of the surveillance isolates were susceptible to moxifloxacin at ≤1 mg/L. Moxifloxacin may therefore be a useful drug for the treatment of patients with pneumococcal infections due to antibiotic-resistant strains or those with severe invasive disease.