Heart valve diseases, such as aortic valve stenosis (AS) and mitral valve regurgitation (MR), are leading causes of heart failure. However, myocardial proteome studies in AS and MR are extremely rare. We profiled the proteome of 75 human left ventricular myocardial biopsies (AS=41, MR=17, controls=17) and detected disease- and sex-specific protein expression alterations. Patients with AS, for example, showed higher abundance of fibrosis-related proteins and lower abundance of proteins related to energy metabolism and protein synthesis capacity with prominent sex differences. This might explain the higher amount of myocardial mass and fibrosis and lower systolic cardiac function especially observed in male AS in our cohort and might help to find specific proteins as treatment targets. Our work provides detailed insight into myocardial protein alterations in AS and MR and expands, in combination with clinical parameters, the understanding of cardiac remodeling in female and male patients, aiming to improve disease- and sex-specific therapy.