Aims:After 4 weeks on a high-fat (HF)-diet containing saturated long-chain fatty acids, rats developed an insulin resistance, as measured by euglycemic hyperinsulinemic clamp. Flavonoids like quercetin have been repeatedly shown to influence glucose and lipid metabolism. Thus the aim of the study was to investigate the impact of quercetin on lipid metabolism and insulin resistance. Methods: Rats (3 groups, n=10 each) were fed a high-fat-diet with (HFQ) or without (HF) the addition of 0,03% quercetin over 4 weeks, a standard (C)-diet fed group served as control. Dietary effects on glucose and lipid metabolism were monitored by measuring body weight gain and -composition, plasma metabolites and hormones and the HOMA-index (tab.1). Results: After the 4-week feeding period, Quercetin did not affect body composition, body weight gain and serum leptin levels. The HFQ- diet decreased glucose, triacylglycerols, insulin concentrations compared to HF-animals. Negative effects of high fat intake were partially prevented by quercetin including significantly lower HOMA-index, triacylglycerols and distinctive higher adiponectin concentrations.