Purpose The purpose of this study was to assess the role of magnetic resonance imaging (MRI) in the assessment of diastolic function using left ventricular diastolic mitral inflow parameters in patients with clinically suspected infiltrative cardiomyopathies. Materials and Methods This study included 21 patients (13 men and 8 women; mean age, 55 years; range, 25-78 years) with suspected infiltrative cardiomyopathies. Among them, 12 patients diagnosed as cardiac amyloidosis (n=11) and sarcoidosis (n=1) histologically. Six patients were ruled out based on MRI findings and three patients histologically. Phase-contrast MRI images of mitral inflow were obtained in the left ventricle to quantify diastolic blood flow. MRI measurements of diastolic parameters were compared (Spearman���s rho correlation) with echocardiographic diastolic mitral inflow velocity parameters. Additional analysis was performed comparing (student t-test with Bonferroni's correction) MRI findings in patients who diagnosed as infiltrative cardiomyopathy (n=12) or not (n=9). Results Blood flow in the mitral valve was successfully imaged by MR for all patients (21/21, 100%) while transthoracic echocardiography evaluated flow in 19 of 21 (90%) patients. For the 19 patients, early diastolic (E) peak velocity was 80 짹 25 cm/s using MRI versus 91 짹 19 cm/s using echocardiography (Spearman���s rank correlation 0.627, P = 0.004), and late diastolic (A) peak velocity was 51 짹 24 cm/s using MRI and 48 짹 25 cm/s using echocardiography (Spearman���s rank correlation 0.57, P = 0.01). E/A ratio was 1.8 짹 0.9 using MRI and 2.4 짹 1.3 using echocardiography (Spearman���s rank correlation 0.67, P =0.002). Deceleration times in both modalities showed limited correlation (MRI, 195 짹 89 ms vs echocardiography, 191 짹 71 ms; Spearman���s rank correlation 0.56, P = 0.013). MRI E/A ratio for peak velocity was significantly higher in patients diagnosed infiltrative cardiomyopathy (2.18 짹 1.06) versus those without (1.38 짹 0.44, P=0.04). Conclusion Mitral inflow peak velocities, deceleration times, and E/A ratios detected using phase-contrast MRI with clinically suspected patients with infiltrative cardiomyopathy showed good correlation with echocardiography.