['Oxidative stress occurs in chronic renal failure patients undergoing hemodialysis (HD). The objective of our study was to measure oxidation products of cholesterols, so-called oxysterols, in the serum of HD patients in comparison to healthy control persons.', 'In 42 HD patients, plasma oxysterols were measured before and after HD. The values were compared with those in 40 healthy controls. The following cholesterol derivatives were analyzed: dienes, 7beta-OH, beta-epoxy, alpha-epoxy, 20alpha-OH, alpha-triol, and 7-keto cholesterol.', 'In HD patients, serum levels of oxysterols are increased in comparison to controls. The highest values were measured for beta-epoxy cholesterol and for 20alpha-OH cholesterol. During HD oxysterol concentrations increased, obviously by water removal and concentration of nondialyzable compounds.'] Are oxysterols increased in plasma of end-stage renal disease patients?