Purpose To determine whether quantitative tissue characterization with T1 and T2 mapping supports recognition of myocardial involvement in patients with systemic sarcoidosis. Materials and Methods Fifty-three consecutive patients with a biopsy-proven extracardiac diagnosis of systemic sarcoidosis (21 men; median age, 45 years; interquartile range, 22 years) and 36 normotensive previously healthy control subjects (14 men; median age, 43 years; interquartile range, 18 years) underwent cardiovascular magnetic resonance imaging, which was performed to assess cardiac function and late gadolinium enhancement, and T1 and T2 mapping. A follow-up substudy was performed in 40 patients (mean follow-up interval, 144 days ± 35 [standard deviation]); of these 40 patients, 18 underwent anti-inflammatory treatment for systemic symptoms. Binary logistic regression and receiver operating characteristic curve analyses were used to assess discrimination between health and disease; Wilcoxon signed rank test was used to assess the effect of treatment. Results When compared with control subjects, patients had higher ventricular volume, higher myocardial native T1 and T2, and lower longitudinal strain and ejection fraction (P < .05 for all). Myocardial native T1 and T2 had higher discriminatory accuracy (area under the receiver operating characteristic curve [AUC]: 0.96 and 0.89, respectively) for separation between control subjects and patients when compared with the standard diagnostic criteria (AUC < 0.67). Native T1 was the independent discriminator between health and disease (specificity, 90%; sensitivity, 96%; accuracy, 94%). There was a significant reduction of native T1 and T2 in the patients who underwent treatment (z score: -3.72 and -2.88; P < .01) but not in the patients who did not (z score, -1.42 and -1.38; P > .15). Conclusion Quantitative myocardial tissue characterization with T1 and T2 mapping may enable noninvasive recognition of cardiac involvement and activity of myocardial inflammation in patients with systemic sarcoidosis. Future studies will be performed to confirm their role in risk stratification and guidance of clinical management. © RSNA, 2017 Online supplemental material is available for this article.