Cardiac magnetic resonance (CMR) is a non-invasive imaging technique that plays a crucial role in the diagnosis, risk stratification, and management of a broad spectrum of cardiovascular diseases. Its high spatial resolution and ability to provide multiparametric tissue characterization make it uniquely suited for evaluating both structural and functional cardiac abnormalities. This review provides a comprehensive and clinically oriented overview of CMR applications in adult cardiology, structured into six main areas: (1) myocardial scarring in ischemic and non-ischemic cardiomyopathies, (2) infiltrative myocardial diseases, (3) adult congenital heart disease, (4) valvular heart disease, (5) pulmonary hypertension and right ventricular morpho-functional evaluation, and (6) cardio-oncology. In addition, technical considerations are also discussed. Finally, recommendations from recent guidelines issued by main international societies are integrated to support clinical decision-making.