Statins, 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitors, are potential drugs for chronic heart failure treatment in clinical studies. However, there may be differences in the effects on heart failure between lipophilic and hydrophilic statins. In this study, we investigated whether hydrophilic rosuvastatin (RSV) and lipophilic pitavastatin (PTV) exert different effects on the left ventricular diastolic function. Subjects were hypercholesterolemia patients with left ventricular diastolic dysfunction. This was an open-label, randomized, parallel, comparative, prospective study. The subjects received treatment with RSV or PTV for 24 weeks, and their low density lipoprotein (LDL)-cholesterol levels were controlled by these statins according to the guideline. The primary endpoint was defined as the change in left ventricle (LV) diastolic function (E/E') estimated by echocardiography, and the secondary endpoint was the plasma B-type natriuretic peptide (BNP) level. No serious adverse effects were observed during the entire study period in any patient, nor were there any significant differences in changes in the body mass index, blood pressure, or heart rate. Statin treatment did not significantly alter the primary endpoint, E/E'. The change ratio of BNP was not significantly different between PTV and RSV groups. However, BNP was significantly increased in the RSV (p=0.030) but not the PTV (p>0.999) group. This study revealed that although neither RSV nor PTV improved LV diastolic dysfunction, BNP, a biomarker of LV wall stress, was increased in the RSV but not the PTV group. Observation for a longer period is necessary to clarify the different effects of these statins on LV diastolic dysfunction. (UMIN-ID: UMIN000003571).