Endomyocardial biopsy (EMB) is an invasive procedure and a diagnostic tool used mainly on the follow-up of post-heart transplant rejection in the past years. Currently, it has an important role in the diagnosis of non-ischemic cardiomyopathies. EMB is frequently performed through a venous access to enter the right ventricle. Diagnostic performance has improved with advances in pathology analysis. Its complications risk, close to 1% in high-volume interventional centers, can be justified considering the potential benefit of an accurate diagnosis and prognosis.