Multivalvular disease (MVD) is a common condition with a complex pathophysiology, dependent on the specific combination of valve lesions. Diagnosis is challenging as several echocardiographic methods commonly used for the assessment of stenosis or regurgitation have been validated only in patients with single valve disease. Decisions about the timing and type of treatment should be made by a multidisciplinary heart valve team, on a case-by-case basis. Several factors should be considered, including the severity and consequences of the MVD, the patient’s life expectancy and comorbidities, the surgical risk associated with combined valve procedures, the long-term risk of morbidity and mortality associated with multiple valve prostheses, and the likelihood and risk of reoperation. The introduction of transcatheter valve therapies into clinical practice has provided new treatment options for patients with MVD, and decision-making algorithms on how to combine surgical and percutaneous treatment options are evolving rapidly. In this Review, we discuss the pathophysiology, diagnosis, and treatment of MVD, focussing on the combination of valve pathologies that are most often encountered in clinical practice.