The Multimapping technique was recently proposed for simultaneous myocardial T-1 and T-2 mapping. In this study, we evaluate its correlation with clinical reference mapping techniques in patients with a range of cardiovascular diseases (CVDs) and compare image quality and inter- and intra-observer repeatability. Multimapping consists of an ECG-triggered, 2D single-shot bSSFP readout with inversion recovery and T-2 preparation modules, acquired across 10 cardiac cycles. The sequence was implemented at 1.5T and compared to clinical reference mapping techniques, modified Look-Locker inversion recovery (MOLLI) and T-2 prepared bSSFP with four echo times (T(2)bSSFP), and compared in 47 patients with CVD (of which 44 were analyzed). In diseased myocardial segments (defined as the presence of late gadolinium enhancement), there was a high correlation between Multimapping and MOLLI for native myocardium T-1 (r(2) = 0.73), ECV (r(2) = 0.91), and blood T-1 (r(2) = 0.88), and Multimapping and T(2)bSSFP for native myocardial T-2 (r(2) = 0.80). In healthy myocardial segments, a bias for native T-1 (Multimapping = 1,116 +/- 21 ms, MOLLI = 1,002 +/- 21, P < 0.001), post-contrast T-1 (Multimapping = 479 +/- 31 ms, MOLLI = 426 +/- 27 ms, 0.001), ECV (Multimapping = 21.5 +/- 1.9%, MOLLI = 23.7 +/- 2.3%, P = 0.001), and native T-2 (Multimapping = 48.0 +/- 3.0 ms, T(2)bSSFP = 53.9 +/- 3.5 ms, P < 0.001) was observed. The image quality for Multimapping was scored as higher for all mapping techniques (native T-1, post-contrast T-1, ECV, and T(2)bSSFP) compared to the clinical reference techniques. The inter- and intra-observer agreements were excellent (intraclass correlation coefficient, ICC > 0.9) for most measurements, except for inter-observer repeatability of Multimapping native T-1 (ICC = 0.87), post-contrast T-1 (ICC = 0.73), and T(2)bSSFP native T-2 (ICC = 0.88). Multimapping shows high correlations with clinical reference mapping techniques for T-1, T-2, and ECV in a diverse cohort of patients with different cardiovascular diseases. Multimapping enables simultaneous T-1 and T-2 mapping and can be performed in a short breath-hold, with image quality superior to that of the clinical reference techniques.