Background: Previous studies demonstrated that adriamycin(AD) aggravates apoptosis of cardiomyocytes and myocardial fibrosis. We observed the effect of olmesartan(OT) on apoptosis rate and myocardial fibrosis in AD induced cardiomyopathy. Materials & Methods: 20 Normotensive Wistar-Koyto rats(WKR) and 20 spontaneously hypertensive rats(SHR) were divided into eight groups AD injected vs. normal saline(NS) injected, placebo vs. OT treated). 2.5mg/kg of AD was injected intraperitonealy twice a week for 3 weeks to four AD treated groups and daily dose of 10 mg/kg OMST was administered orally for 6 weeks to four OT treated groups. Immunohistochemical stain using synthesized CARP antibody and picrosirius stain was performed on left ventricle. The positively stained areas were measured by using an image analysis program(Image Pro-Plus 4.5). The CARP volume fractions (CaVF) and collagen volume fractions (CVF) were calculated. H9C2 cells were cultured and expression of CARP was observed after AD and OT treated. Results: The CaVF of OT treated groups were increased significantly even in AD injected groups. The CVF of AD injected groups increased significantly, compared to NS injected groups in both WKR and SHR respectively. The CVF of OT treated groups decreased significantly in SHR groups. CARP expression of OT treated H9C2 cells were increased but AD suppressed CARP expression whether OT was treated or not. Conclusion: OT treatment increases CARP expression even in AD injected groups and reduced myocardial fibrosis in SHR. OT induces changes in CARP expression in H9C2 cells.