The third most common stroke complication is infection. We studied the rates of aspiration pneumonia and urinary tract infection (UTI), their risk factors and their effect on outcome in the 1455 Glycine Antagonist (Gavestinel) in Neuroprotection (GAIN) International patients with ischaemic stroke. Forward stepwise logistic regression and Cox proportional hazards modelling identified baseline factors that predicted events and the independent effect of events up to day 7 on poor stroke outcome at 3 months in patients alive at day 7, after correcting for prognostic factors. Higher baseline National Institute of Health Stroke Scale (NIHSS) and age, male gender, history of diabetes and stroke subtype predicted pneumonia, which occurred in 13.6% of patients. Female gender and higher baseline NIHSS and age predicted UTI, which occurred in 17.2% of patients. Pneumonia was associated with poor outcome by mortality (hazard ratio, 2.2; 95% confidence interval, 1.5-3.3), Barthel index (<60) (odds ratio, 3.8; 2.2-6.7), NIHSS (4.9; 1.7-14) and Rankin scale (>/=2) (3.4; 1.4-8.3). UTI was associated with Barthel index (1.9; 1.2-2.9), NIHSS (2.2; 1.2-4.0) and Rankin scale (3.1; 1.6-4.9). Pneumonia and UTI are independently associated with stroke poor outcome. Patients with identified risk factors must be closely monitored for infection.