Objective: To investigate the effects of estrogen on left ventricle (LV) mass and collagen deposition, and on the expression of receptors for estrogen (ERα, ERβ) and Ang II (AT₂R, AT₁R) in the heart of aged female rats. Methods: Aged (∼12 months old) intact (n=7), ovariectomized plus placebo (OVX, n=7), and estrogen-replaced (E2, n=6) as well as young (∼3 months old, n=4) female Sprague–Dawley rats were used in this study. After 1 month of treatment, the left ventricular weight/body weight ratio (LVW/BW), changes in myosin heavy chain expression (MHC), matrix metalloproteinase (MMP)-2 activity, the collagen I/III ratio, and the expression of ERs and Ang II receptors in the LV were evaluated. Results: In aged rats, OVX increased LVW/BW associated with a higher expression of β-MHC isoform, increased collagen I/III ratio, and decreased MMP-2 activity compared to intact rats. Furthermore, the OVX group had a decrease in ERs α and β as well as AT₂R but an increase in AT₁R expression. Estrogen replacement prevented the effects of ovariectomy on heart remodeling as well as increased further expression of ERβ and decreased AT₁R expression. Conclusion: Removal of ovarian hormones increased LV remodeling in the aged rat, which could be attenuated by estrogen replacement. Moreover, regulation of Ang II receptor expression could be a mechanism by which estrogen may modulate heart remodeling.