Soluble epoxide hydrolase (sEH) catalyzes the hydrolysis of exogenous and endogenous epoxides to vicinal diols. Endogenous substrates for sEH include epoxyeicosatrienoic acids (EETs) which exhibit vasodialatory and anti-inflammatory activity. Small molecule inhibitors of sEH may therefore hold promise as therapeutics for the treatment of hypertension and vascular inflammation. The fluorescence-based sEH Inhibitor Screening Assay Kit provides a convenient method for screening epoxide hydrolase inhibitors. The assay utilizes (3-phenyl-oxiranyl)-acetic acid cyano-(6-methoxy-naphthalen-2-yl)-methyl ester (PHOME) as a substrate. Hydrolysis of PHOME by epoxide hydrolase produces the highly fluorescent 6-methoxy-2-naphthaldehyde which can be analyzed using an excitation wavelength of 330 nm and emission wavelength of 465 nm. Each kit contains buffer, substrate, and sufficient human recombinant sEH for 100 tests.