The intake of polyunsaturated fatty acids (PUFAs) is generally linked with a reduced cardiovascular disease (CVD) risk, but an elevated n6PUFA intake, without simultaneous n3PUFA supply, may elevate the risk. PUFAs are suspected as being easily oxidized and have a potential role in lipoprotein oxidation and inflammation. Saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) are resistant to oxidation. However, in a Western diet, their most important source is red meat, a food stuff rich in heme iron which can catalyze oxidative reactions. Therefore, different serum fatty acid (FA) proportions (free + esterified) were correlated with the status of low-density lipoprotein (LDL) oxidation in vivo (conjugated dienes = oxLDLlipids and antibody-based oxidized proteins = oxLDLprot) and inflammation (serum CRP) in 2196 Finnish subjects (age: 24-39 years) using CVD risk factor-adjusted linear regression models. High n6PUFA, PUFA/SFA and n6/n3 ratios, and low SFA and MUFA were all associated with reduced levels of oxLDLlipids, oxLDLprot, and CRP. These findings at the population level suggest that PUFAs are negatively and SFAs and MUFAs positively related with LDL oxidation and inflammation; these conclusions are in line with previous observations linking PUFAs, particularly n6PUFAs, with lower CVD risk, and SFAs with increased risk.