The invention relates to the combination of inhibitors of phosphodiesterase 1 (PDE1) and inhibitors of Neprilysin (NEP) useful for the treatment of certain cardiovascular diseases or related disorders, e.g., hypertension, congestive heart disease, and post-myocardial infarction. In another embodiment, the invention relates to the combination of inhibitors of PDE1 and inhibitors of NEP for the treatment of diseases or disorders characterized by disruption of or damage to various cGMP/PKG mediated pathways in the cardiovascular system (e.g., in cardiac tissue or in arterial smooth muscle).