Modifications in the structure of native LDL that are capable of inducing aggregation and/or fusion of the particles are currently recognized to be a prerequisite for the initiation of lipid accumulation in arterial intima. Modified forms of LDL can play an important role on atherogenesis and atherosclerosis progression, inducing atherosclerosis through complex inflammatory and immunological mechanisms. LDL can be modified by oxidation, glycation, alkylation and nitration, among other reactions. All modifications of LDL can generate neoepitopes, which become LDL immunogenic. Since modified forms of LDL are associated with several pathological states, monitoring their levels in human plasma would be very useful for studying atherogenesis. Monoclonal antibodies are powerful tools in identifying specific structures on heterogeneously modified LDL particles. Monoclonal antibodies specific for epitopes on modified lipoproteins have been obtained and used for developing diagnosis kits to evaluate the concentrations of modified lipoproteins in blood plasma and other biological fluids. Most of the tests concerning to the assay of modified LDL are ELISAs. More recently, immunosensor systems, based on the biosensor technologies, begin to be developed. In this review, the recent advances on the assessment of these modified LDL particles and related patents will be discussed.