Fundação Oswaldo Cruz (FIOCRUZ), Centro de Tecnologias Estratégicas do Nordeste (CETENE), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) e Fundação de Apoio ao Desenvolvimento Científico de Pernambuco (FACEPE).AIMS: The present study investigated the effect of a maternal diet rich in omega-6 (E6D) or omega-9 (E9D) on atherogenesis in the offspring of mice. MAIN METHODS: LDL receptor-deficient mice were fed a diet rich in either omega-6 (E6D) or omega-9 (E9D) for 45 days prior to mating and until the birth of the offspring, evaluating the effect on the offspring aorta in comparison to a standard diet (STD), by immunohistochemical analysis, morphometric analysis and electron microscopy. KEY FINDINGS: Hypercholesterolemic female mice fed E6D generated offspring with high levels of total cholesterol, triglycerides (TG) and CC-chemokine ligand 2/monocyte chemoattractant protein 1 (CCL2/ MCP-1) as well as a reduction in high-density lipoprotein. The ascending aorta of these animals exhibited an increase in arterial wall thickness as well as increased expression of CCL2/MCP-1 and vascular cell adhesion molecule 1. The ultrastructural analysis revealed severe alterations in endothelial cells. The offspring from mothers fed E9D exhibited a reduction in TG and an increase in low-density lipoprotein. The ultrastructural analysis revealed a well-preserved aortic endothelium in these animals. SIGNIFICANCE: The results suggest that hypercholesterolemic mothers feed a diet rich in omega-6 predispose their offspring to endothelial dysfunction.