THE Irish census is an unreliable method of enumerating centenarians. In the four censuses 1951, 1961, 1971 and 1981, the number of centenarians has increased erratically1. Two independent methods of predicting the number or centenarians, both extrapolating from life tables, give very similar and much lower predictions for 1981 than reported in the census. During the period 1961–1981 the calculated number of centenarians has increased five-fold in England and Wales but has only doubled in the Republic of Ireland. Among the very old there are relatively small numbers reported as dying from myocardial infarction and malignant neoplasms and an increased number of deaths reported as from pneumonia.