We investigated the predictors of cardiovascular mortality at different ages in a longitudinal study of 10186 hypertensive patients attending clinics in the UK. There were 7374 patients (51% were men) < 60 years of age and 2799 patients (44% men) were > or = 60 years. For IHD death the age-adjusted relative risks (RRs) and 95% confidence intervals (CI) for a 1 mmol/l increase in cholesterol were RR = 1.17 (1.07, 1.27) (men) and RR = 1.22 (1.12, 1.33) (women). The RRs for stroke were 0.99 (men) and 1.07 (women). In men and younger women, urea and smoking were important predictors of IHD and stroke death. Age differences were present in women for both urea and smoking. For IHD in women, smoking: RR = 2.65 (1.80, 3.89) (< 60 years) and RR = 1.38 (1.01, 1.88) (> or = 60 years). For stroke in women, smoking: RR = 2.03 (1.23, 3.35) (< 60 years) and RR = 1.06 (0.70, 1.61) (> or = 60 years). We conclude that urea and smoking are important risk factors for stroke and IHD death in hypertensive women aged < 60 years, but are less important in those aged over 60 years. Cholesterol predicted IHD death in all men and women, but did not predict stroke death.