To objective of this study was to determine if physiologically relevant levels of omega‐6 (n6) and omega‐3 (n3) fatty acids in the Total Western Diet (TWD) affect the acute inflammatory response in C57 mice challenged with LPS. The TWD is a new rodent diet that was formulated to match the macronutrient and micronutrient intakes of Americans and is based on data collected in 2009‐2010 in NHANES. Thirty‐two mice were randomly assigned to one of four versions of the TWD differing in n6 and n3 content. Based on NHANES, a typical Western Diet contains 7% kcal from n6 and 0.7% kcal n3. The diets used in this 2 x 2 design reflected the 10th and 90th percentile of n6 and n3 intakes. All diets contained 34% kcal from fat with the following n6 and n3 compositions (all in kcal): HH (10.4% n6, 1.1% n3 (10:1 ratio)), HL (10.4% n6, 0.4% n3 (26:1 ratio)), LH (5.1% n6, 1.1% (5:1 ratio)) and LL (5.1% n6, 0.4% n3 (13:1)). After 28d mice were challenged with 10mg/kg of an intraperitoneal injection of lipopolysaccharide (LPS), sacrificed after 24 h and plasma and tissues were collected. Fatty acids were measured in erythrocytes using gas chromatography and plasma cytokines were measured using a multiplexed bead assay. Mice fed the HH diet gained more 29% more weight than LH diet and 39% more than those fed the LL diet. The erythrocyte fatty acid profile indicated the LH group had significant more DHA and DPA than other diet groups, and higher EPA than HL and LL groups. Arachidonic acid, on the other hand, was not different between groups. Despite the differences in PUFA intakes there were no significant difference between the groups in the pro‐inflammatory and anti‐inflammatory cytokines in plasma. According to these results, dietary n6 and n3 PUFA at intakes physiologically relevant to the US diet did not affect the acute inflammatory response to LPS.Grant Funding Source: USDA‐NIFA