Hyperlipidemia is a well-established risk factor for cardiovascular diseases. Trillions of people worldwide display mildly elevated levels of plasma lipids and cholesterol due to diet and life-style. The relationship between severe hyperlipidemia and thrombosis has been extensively investigated, but the effects of the preliminary stages of hyperlipidemia on platelet function are unclear. Therefore, we investigated how moderate elevation of different plasma lipid profiles influence platelet activation and thrombus formation, as compared to higher plasma lipid concentrations. Hyperlipidemic Apoe-/- and Ldlr-/- and wild-type mice were fed a normal chow diet, resulting in mildly increased plasma cholesterol. Blood from both knockout mice was used in comparison to wild-type mice, for multiparameter ex vivo measurements of thrombus formation under flow. Whole blood (fibrin-)thrombus formation on collagen in the absence or presence of coagulation (with(out) tissue factor), indicated enhancement of the thrombotic process in both knockout mice. These effects were not further aggravated in aged mice, as well as in Apoe-/- mice on high fat diet with very high plasma cholesterol levels. Bone marrow chimeras of wild-type or Ldlr-/- platelets into irradiated Ldlr-/- recipient mice showed similar thrombus formation patterns. This suggested that hyperlipidemia itself, not the platelet LDL receptor deficiency is responsible for the altered platelet activation status in Ldlr-/- mice. Exploration of the platelet proteome revealed high similarity between the three genotypes, although some proteins showed significantly changed expression in Apoe-/- mice. Finally, platelet lipidomic analysis showed an increased lipid profile in mildly hyperlipidemic mice, which may further contribute to the observed prothrombotic phenotype