Histological sections of spleen and both kidneys from 372 necropsies were examined for the presence of cholesterol emboli. These were identified in nine (2.4%) cases and the clinical histories of these cases were reviewed. All the subjects with cholesterol emboli were older than 60 years and eight out of nine were male. Lesions of differing ages were found in individual cases, suggesting that the process of embolism was recurrent. Two of the cases had undergone arteriography procedures in the month before death and, if these were excluded, then the incidence of "spontaneous" cholesterol embolism was 1.9%. This incidence is much lower than that of previously published studies and may be due to a lower incidence of cholesterol embolism in Britain compared with North America or a decrease in incidence over the past two decades. In three of the subjects with cholesterol embolism the cause of death could be related to systemic atherosclerosis, but in the other six cases there was no apparent correlation between the finding of cholesterol embolism and the cause of death. The clinical relevance of the histological finding of cholesterol embolism can only be assessed in conjunction with clinical information.