BACKGROUND: Subjects with type 2 diabetes (T2D) and their relatives (REL) carry an increased risk of cardiovascular disease (CVD). Low-grade inflammation, an independent risk factor for CVD, is modifiable by diet. Subjects with T2D show elevated postprandial inflammatory responses to fatrich meals, while information on postprandial inflammation in REL is sparse. AIM: To clarify whether medium-chain saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) have differential acute effects on low-grade inflammation in REL compared to controls (CON). METHODS: In randomized order, 17 REL and 17 CON ingested two fat-rich meals, with 72 energy percent from MUFA and 79 energy percent from mainly medium-chain SFA, respectively. Plasma high sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), adiponectin, and leptin were measured at baseline, 15 min, 60 min, and 240 min postprandially. Muscle and adipose tissue biopsies were taken at baseline and 210 min after the test meal, and expression of selected genes was analyzed. RESULTS: Plasma IL-6 increased (p < 0.001) without difference between REL and CON and between the meals, whereas plasma adiponectin and plasma hs-CRP were unchanged during the 240 min observation period. Plasma leptin decreased slightly in response to medium-chain SFA in both groups, and to MUFA in REL. Several genes were differentially regulated in muscle and adipose tissue of REL and CON. CONCLUSIONS: MUFA and medium-chain SFA elicit similar postprandial circulating inflammatory responses in REL and CON. Medium-chain SFA seems more proinflammatory than MUFA, judged by the gene expression in muscle and adipose tissue of REL and CON.