Monocytes are key players in inflammatory processes which are triggered by lipopolysaccharide (LPS), the major outer membrane component of gram-negative bacteria. The present study in human monocytic THP-1 cells was designed in order to identify LPS-inducible genes which are down-regulated by the reduced form of CoQ10 (ubiquinol, Q10H2). For this purpose, THP-1 cells were incubated with 10 M Q10H2 for 24 h. Subsequently, cells were stimulated for 4 h with 1g/ml LPS and the resulting gene expression levels were determined using microarrays. 14 LPS-inducible genes were identified to be significantly (p < 0.05) down-regulated by Q10H2 pre-treatment between a factor of 1.32 and 1.65. The strongest effect of Q10H2 incubation was found for the nuclear receptor coactivator 2 gene (NCOA2). Gene Ontology (GO) terms revealed for the Q10H2-sensitive genes an involvement in e.g. signal transduction processes (CENTD1, NCOA2, PSD3, PPP2R5C), transcriptional regulation (NCOA2, POU2F1, ETV3) and cell proliferation pathways (CCDC100, EPS15). In conclusion, we provide evidence in THP-1 cells that the reduced form of CoQ10 (Q10H2) modulates LPS-induced gene expression.