Intensified oxidative modification of proteins and increased concentration of advanced oxidation protein products (AOPPs) are confirmed by many experimental investigations in different pathological states, especially these with well-known participation of oxidative stress (OS) in etiopathogenesis but also these with not well recognized its role. Presented data indicate that AOPPs play a significant role in many disorders with chronic background, because of they reflect both intensification of OS and the degree of pathological changes connected with OS in these diseases. This review sets out the clinical and diagnostic aspects of AOPPs in these diseases such as: renal diseases with different etiology, cardiovascular diseases, as well as connected with metabolic disturbances – e.g. diabetes, atherosclerosis or metabolic syndrome. Moreover results of investigation about utility of AOPPs measurement, mainly in plasma/serum, in these diseases are presented. The review and evaluation of application of AOPPs as useful marker in diagnosis, prognosis and monitoring the course of these diseases were performed. This paper also describes the suggested mechanisms of their action which contribute to biochemical and clinic changes undergoing in the condition of increased OS. Diagnostic or prognostic utility of AOPPs are especially indicated in the course of diabetes and its complications (diabetic nephropahy) and cardiovascular diseases.