Abstract Objective Percutaneous transluminal angioplasty (PTA) of the internal jugular veins (IJVs) has been proposed in recent years to treat chronic cerebrovascular venous insufficiency, with discordant results. Moreover, very little is known about the efficacy of PTA in restoring a normal cerebral venous outflow. The aim of this study was to investigate the anatomic factors and patient characteristics that might influence the efficacy of PTA of the IJV. Methods There were 797 consecutive patients with venous outflow anomalies who underwent standardized, operator-independent catheter venography and PTA of the IJVs. Before and after PTA, morphologic and hemodynamic anomalies of the IJVs were documented. The primary end point of the study was to evaluate the morphologic factors influencing the efficacy of angioplasty in improving IJV outflow. Results PTA resulted in an increased outflow through the IJVs in most patients. However, younger individuals with transverse endoluminal defects and higher pre-PTA flows are more likely to respond well to PTA compared with those who exhibit hypoplasia, stenosis, or longitudinal endoluminal defects. Conclusions This study identified the factors that influence and could predict the efficacy of PTA in the treatment of IJV anomalies.