Introduction: There is increasing evidence that consumption of cocoa products have a beneficial effect on cardio-metabolic health, but the underlying mechanisms remain unclear. Cocoa contains a complex mixture of flavan-3-ols. Epicatechin, a major monomeric flavan-3-ol, is considered to contribute to the cardio-protective effects of cocoa. We investigated effects of pure epicatechin supplementation on whole genome gene expression profiles of circulating immune cells. Methods: In a randomized, double blind, placebo-controlled cross-over trial, 37 (pre)hypertensive (40-80y) subjects received two 4-week interventions; epicatechin (100mg/day) or placebo with a wash-out period of 4-week between both interventions. Whole genome gene expression profiles of peripheral blood mononuclear cells were determined before and after both interventions. Results: After epicatechin supplementation 1180 genes were significantly regulated, of which 234 were also significantly regulated compared to placebo. Epicatechin supplementation up-regulated gene sets involved in transcription/translation and tubulin folding and down-regulated gene sets involved in inflammation. Only a few genes within these regulated gene sets were actually significantly changed upon epicatechin supplementation. Upstream regulators that were shown to be inhibited were classified as cytokine or inflammatory type molecules. Conclusion: Pure epicatechin supplementation modestly reduced gene expression related to inflammation signalling routes in circulating immune cells. These routes are known to play a role in cardiovascular health.