The Expert Panel on Blood Rheology of the International Council for Standardization in Haematology (ICSH) has prepared new recommendations for measurement of the erythrocyte sedimentation rate (ESR) under the following categories: 1. ICSH reference method-ICSH now recognises, as its reference method for the ESR, the sedimentation of EDTA-anticoagulated but undiluted blood in traditional Westergren pipettes that meet ICSH specifications. 2. ICSH standardised method-ICSH recommends specifications for a new standardised method for the ESR based on the sedimentation of EDTA-anticoagulated, but undiluted blood in pipettes with a 200 mm scale and which are designed to avoid spillage of blood or aerosol generation. This standardised method may be used for verification or quality control of other ESR methods and, in future, may replace the reference method. 3. ICSH selected methods-ICSH recommends specifications for working methods, using diluted or undiluted blood, which may be considered as ICSH selected methods for routine use. A protocol is outlined for evaluation of such working methods against the ICSH reference method or the new ICSH standardised method.