In a large, population-based cohort of post-menopausal women free of cardiovascular disease, use of MHT is not associated with adverse, subclinical changes in cardiac structure and function. Indeed, we demonstrate significantly smaller LV and LA chamber volumes which have been linked to favourable cardiovascular outcomes in other settings. Our findings provide a novel way to examine the impact of MHT on the cardiovascular system; future work will focus upon linkage of MHT use and CMR parameters to cardiovascular outcome data.