['Polyunsaturated fatty acids are essential nutrients for the normal development of the brain. We investigated the associations between plasma polyunsaturated fatty acids and cognition in normal weight and overweight children.', "The study recruited 386 normal weight children and 58 overweight children aged six to eight years and blood samples were drawn after a 12-hour fast. We assessed plasma polyunsaturated fatty acids using gas chromatography, cognition using Raven's Coloured Progressive Matrices, and overweight and obesity using the age-specific and sex-specific cut-offs from the International Obesity Task Force. The data were analysed by linear regression analyses adjusted for age and sex.", "Higher proportions of eicosapentaenoic acid in plasma triacylglycerols (β\xa0=\xa00.311, p\xa0=\xa00.020, p\xa0=\xa00.029 for interaction) and docosahexaenoic acid in plasma triacylglycerols (β\xa0=\xa00.281, p\xa0=\xa00.038, p\xa0=\xa00.049 for interaction) were both associated\xa0with higher Raven's scores in overweight children but not in normal weight children. Higher eicosapentaenoic acid to arachidonic acid ratios in triacylglycerols (β\xa0=\xa00.317, p\xa0=\xa00.019) and phospholipids (β\xa0=\xa00.273, p\xa0=\xa00.046) were directly associated with the Raven's score in overweight children but not in normal weight children."] Are plasma polyunsaturated fatty acids directly associated with cognition in overweight children but not in normal weight children?