One hundred and ninety-four elderly subjects living in the community were randomly selected in order to define a reference range for erythrocyte sedimentation rate (ESR) for this age group. Mean (S.D) values were 4.1 (2.9) mm in one hour and 7.2 (2.6) mm in one hour for men and women respectively. Values ranged from 0-44 mm in one hour. The ESR showed significant independent correlations with fibrinogen, haemoglobin (male and female) and albumin levels (male only). A new algorithm for determination of the upper limit of normal for age is proposed: Females ESR = Age/3 + 10 Male ESR = Age/3.