BACKGROUND: The study was carried out to evaluate the effects of short-term transdermal hormone replacement therapy (HRT) on glycaemic control, lipid metabolism, C-reactive protein (CRP) and proteinuria in high-risk postmenopausal women. METHODS: A total of 20 well-controlled type 2 diabetic, hypertensive and 21 well-controlled glucose-tolerant, hypertensive postmenopausal women were prospectively enrolled. After 12 weeks of transdermal HRT, the changes in serum lipid sub-fractions, fasting glucose, fructosamine, glycated haemoglobin (HbA(1c)), CRP, creatinine, 24 h urine protein levels, creatinine clearance and blood pressure were evaluated. RESULTS: After 12 weeks of treatment, serum total-cholesterol and low-density cholesterols (LDL-cholesterol) appeared slightly reduced and serum triglyceride slightly elevated, although non-significantly so in both groups. The increase in HDL-cholesterol (P < 0.05) and reduction in very low density (VLDL)-cholesterol (P < 0.05) levels were significant in hypertensive patients. Elevation in the Apolipoprotein A1 (P < 0.05) and reduction in the Apolipoprotein B (P < 0.05) levels were statistically significant in all patients. HRT was associated with significant decreases in serum fasting glucose (P < 0.05) and fructosamine (P < 0.05) levels in diabetic patients. Serum HbA(1c), CRP, creatinine, 24 h urine protein levels, creatinine clearance and systolic and diastolic blood pressure did not change significantly in either group. CONCLUSIONS: There were no detrimental effects of transdermal HRT on lipid profile, glucose metabolism, CRP and urine protein levels in our well-controlled diabetic or hypertensive patients. A decision regarding HRT use should be taken on a case-by-case basis.