The course of dilated cardiomyopathy in New Zealand was studied in 72 cases that were followed up for less than or equal to 10 years after cardiac catheterisation and coronary angiography. Eighty one per cent were male and 86% were white; the remainder were Maori. The mean age of patients at the time of investigation was 50 X 15 years. Most patients were unskilled labourers. The commonest presenting symptom was dyspnoea and the commonest physical sign was cardiomegaly. Mean survival time from first hospital presentation was 85 months; half the deaths were sudden. Factors predicting a poor survival included cardiomegaly, age, arrhythmias, cigarette smoking, and subclinical thiamine deficiency. The syndrome of dilated cardiomyopathy in New Zealand appears to be identical with that seen in other European populations.