The objective of this study was to determine which personal, environmental and occupational factors were associated with risk of non-fatal ischaemic heart disease in a group of 3930 white underground miners born between 1916 and 1930. Evidence of previous myocardial infarction, based on their electrocardiograms and answers to the Rose questionnaire, was found in 179 men who were taken as the cases of interest. Because of difficulties in coding the occupational histories of all available miners, a representative sample of the remaining 'non-infarct' miners was drawn as a reference sample. Univariate analysis of the 179 cases and 669 referents showed that the personal factors such as age, systolic and diastolic blood pressure, serum cholesterol and smoking were significantly different in the two groups at the 1% level of significance. Logistic regression analysis showed similarly that these same variables were significantly associated with IHD when included in a multivariate model. None of the environmental and occupational variables was significant.