Purpose: The aim of this study was to evaluate the influences of adriamycin on myocardial contractile function and myocardial fibrosis in hypertension. Methods: We divided 20 Spraque-Dowley rats (SDR) and 16 spontaneously hypertensive rats (SHR) into 4 groups[5 saline treated SDRs ( SDR-ND group), 4 saline treated SHRs (SHR-NS), 15 adriamycin-treated SDRs(SDR-ADR group) and 12 adriamycin-treated SHRs(SHR-ADR group)]. Adriamycin was administrated intraperitoneally for 3 weeks for total cumulative dose of 15 mg/kg body weight. Transthoracic echocardiography with a 15MHz linear array was performed before and after injection. At 3 weeks after injection, collagen volume fractions (CVF) was measured with Imagepro-plus program in the heart tissue stained with picrosirius red.(See figure) Result: 1. After injection of ADR, fractional shortening decreased significantly.(p<0.005 versus SDR-NS and SHR-NS, respectively) 2. CVF of myocardial interstitium is 1.02짹0.18% in SDR-NS, 3.93짹3.13% in SDR-ADR, 3.17짹1.10% in SHR-NS and 6.79짹1.50% in SHR-ADR.(p<0.05 versus SDR-NS, SDR-ADR and SHR-NS, respectively) 3.CVF of perivascular portion was 1.22짹0.67% in SDR-NS, 5.48짹5.23% in SDR-ADR 5.58짹1.25% in SHR-NS and 12.3짹4.18% in SHR-ADR (p<0.05 versus SDR-NS, SDR-ADR and SHR-NS, respectively) Conclusion: Adriamycin deteriorates the interstitial and perivascular fibrosis in hypertensive heart. Thus adriamycin should be cautiously administrated in hypertensives for prevention of cardiac toxicity.