The European Cancer Anaemia Survey (ECAS) was conducted to prospectively evaluate the prevalence, incidence and treatment of anaemia (haemoglobin <12.0 g/dL) in European cancer patients, including the relationship of mild, moderate and severe anaemia to performance status. Patients were evaluated for up to 6 months. Data (N=15367) included demographics, tumour type, performance status, haemoglobin levels, cancer treatments and anaemia treatments. Prevalence of anaemia at enrollment was 39.3% (haemoglobin <10.0 g/dL, 10%), and 67.0% during the survey (haemoglobin <10.0 g/dL, 39.3%). Low haemoglobin levels correlated significantly with poor performance status. Incidence of anaemia was 53.7% (haemoglobin <10.0 g/dL, 15.2%). Anaemia was treated in 38.9% of patients (epoetin, 17.4%; transfusion, 14.9%; and iron, 6.5%). Mean haemoglobin to initiate anaemia treatment was 9.7 g/dL. Anaemia prevalence and incidence in cancer patients are high. Anaemia significantly correlates with poor performance status and many anaemic patients are not treated.