Background and aim: Hybrid Positron Emission Tomography/Magnetic Resonance Imaging (PET/MRI) is a new multimodality technique with a promising future in diagnostic imaging, allowing the synchronous acquisition of MRI anatomical data and PET functional information. The present systematic review aims to update the latest available evidence on the role of PET/MRI in the management of non-ischemic cardiovascular diseases, such as inflammatory cardiomyopathies, infiltrative disorders, vasculitis, and cardiac tumors. Furthermore, some examples extrapolated from the case histories of our center have been reported. Materials and methods: The literature search was conducted on PubMed, with particular attention to articles published in the last 5 years. The terms used were “PET/MRI” OR “PET/MR” AND “cardiovascular” AND “inflammation” NOT “ischemic”. All relevant full-text articles found were evaluated. We have then separated the information found into categories, starting from the division between vascular and cardiac pathologies, and a comprehensive narrative review of the literature was written. Results: The research has produced 214 articles; 86 were eligible for the review. It has emerged that PET/MRI can facilitate the distinction between active and chronic disease in patients with endocarditis, myocarditis, vasculitis and aortitis. In sarcoidosis, it allows to detect fibrous areas due to the presence of granulomas and in amyloidosis, it identifies areas of accumulation of amyloid. In cardiovascular masses, PET/MRI helps to distinguish benign from malignant masses due to increased metabolism in malignant tumors. Conclusion: The current review confirms the utility of PET/MRI in providing a comprehensive assessment of non-ischemic cardiovascular diseases.