We investigated the prevalence of anaemia (haemoglobin concentration < 12 g/dl) in 336 women with early-stage breast cancer and its association with other known prognostic factors. The median follow-up period was 60.5 months (range 9 123 months). Seventy-nine women (23.5%) had a low pre-treatment haemoglobin concentration, but anaemia was not correlated with age, tumour size, nodal status, histological grade or hormone receptor status. Univariate analysis revealed that disease-free survival and overall survival were shorter in patients with anaemia at the time of diagnosis than in patients with normal haemoglobin concentrations. Anaemia remained a significant prognostic factor for disease-free survival and overall survival in the multivariate analysis (relative risk, 1.884 and 1.785, respectively). These results suggest that pre-treatment haemoglobin concentration is an independent prognostic factor in patients with early-stage breast cancer.