Abstract: The chemiluminescence reaction of luminol with reducing agents was examined by a flow injection method. It was found that Chemiluminescence was directly produced by the reaction of reducing agents with luminol in the presence of a catalyst in an alkaline solution. Hexacyanoferrate(III) and hexacyanoferrate(II) were used as catalyst for the reaction. Detection limits (S/N=3) of uric acid, phenacyl alcohol, cortisone, ascorbic acid, corticosterone, glutathione, cysteine, fructose, glucose and creatinine were 1.7 pmol, 3.0 pmol, 4.0 pmol, 6.0 pmol, 16.0 pmol, 55.0 pmol, 62.0 pmol, 0.6 nmol, 1.5 nmol and 15.0 nmol, respectively.