One-thousand-and-seventy-one randomly chosen elderly persons (537 women, 534 men; median age 80) were recruited from the Institute of Human Aging (Dept of Psychiatry, University of Liverpool). Almost a quarter (23.8%; equal numbers of both sexes) had had shingles (HZ), at a median age of 60 (for both sexes); 39 subjects (3.6% of all respondents, 15% of those who had had shingles), two thirds of whom were female, developed post-herpetic neuralgia (PHN), defined as pain persisting for more than 3 months; they acquired HZ at a median age of 70. In 22 of them, pain had resolved by the time they were questioned, but in 17 it was ongoing (from less than 12 to 504 months). Two new independent risk factors for PHN were identified: (1) female gender; and (2) living alone at the time of HZ acquisition (p = 0.009). In addition to confirming the well-known factor of: (3) age at shingles acquisition (up to the early 90s); and (4) scarring, presumed to be a consequence of rash severity, was significantly commoner in subjects whose HZ was followed by PHN.Extrapolating the prevalence figures to the whole UK population, of whom 9.28 million were over 64 in 1992, it can be conservatively estimated that at any one time, some 200 000 people in the UK have PHN. Copyright 1999 European Federation of Chapters of the International Association for the Study of Pain.