The use of rtPA in stroke patients aged >80 years remains controversial and it is debated whether there are sex-based differences in the response to rtPA. We assessed the clinical value of thrombolytic therapy in patients aged >80 years (elderly group) in comparison with a non-elderly group, and evaluated the existence of sex differences in the response to rtPA. All consecutive patients (n = 157) treated with rtPA were prospectively assessed since July 2001, including 49 elderly patients who fulfilled the National Institute of Neurological Disorders and Stroke (NINDS) criteria. Changes of the National Institute of Health Stroke Scale (NIHSS) score at 1 h, 24 h, and 7 days after rtPA administration, favourable outcome at day 90 [(modified Rankin Scale) mRS 0-1, or 2 if mRS = 2 before the stroke], symptomatic bleedings, and death rates were compared between elderly and non-elderly patients. Using logistic regression, baseline NIHSS score [odds ratio (OR) 0.59, 95% confidence interval (CI) 0.41-0.84] was an independent predictor of favourable outcome, but not sex (OR 0.72, 95% CI 0.33-1.56), or age >80 years (OR 0.74, 95% CI 0.32-1.70). The rates of clinical improvement, mortality, or symptomatic CNS bleeding were also unrelated to age and sex. In conclusion, the response to IV rtPA is not impaired in elderly stroke patients and male and female are equally responsive.