As the importance of pelvic venous disorders (PeVD) has been increasingly recognized, progress in the field has been limited by the lack of a valid and reliable classification instrument. Misleading historical nomenclature, such as the May-Thurner, pelvic congestion, and nutcracker syndromes, often fails to recognize the interrelationship of many pelvic symptoms and their underlying pathophysiology. Based on a perceived need, the American Vein and Lymphatic Society convened an international, multidisciplinary panel charged with the development of a discriminative classification instrument for PeVD. This instrument, the Symptoms-Varices-Pathophysiology ("SVP") classification for PeVD, includes three domains-Symptoms (S), Varices (V), and Pathophysiology (P), with the pathophysiology domain encompassing the Anatomic (A), Hemodynamic (H), and Etiologic (E) features of the patient's disease. An individual patient's classification is designated as SVPA,H,E. For patients with pelvic origin lower extremity signs or symptoms, the SVP instrument is complementary to and should be used in conjunction with the Clinical-Etiologic-Anatomic-Physiologic (CEAP) classification. The SVP instrument accurately defines the diverse patient populations with PeVD, an important step in improving clinical decision making, developing disease-specific outcome measures and identifying homogenous patient populations for clinical trials.