Electronegative low-density lipoprotein (LDL) found in human plasma is highly atherogenic, and its level is elevated in individuals with increased cardiovascular risk. In this review, we summarize the available data regarding the elevation of the levels of electronegative LDL in the plasma of patients with various diseases. In addition, we discuss the harmful effects and underlying mechanisms of electronegative LDL in various cell types. We also highlight the known biochemical properties of electronegative LDL that may contribute to its atherogenic functions, including its lipid and protein composition, enzymatic activities, and structural features. Given the increasing recognition of electronegative LDL as a potential biomarker and therapeutic target for the prevention of cardiovascular disease, key future goals include the development of a standard method for the detection of electronegative LDL that can be used in a large-scale population survey and the identification and testing of strategies for eliminating electronegative LDL from the blood.