PURPOSE: To study the hypothesis of detecting bladder inflammation associated with overactive bladder (OAB) through altered urine levels of cytokines, chemokines, and growth factors. METHODS: Midstream urine specimens were collected from a prospective study done on eight asymptomatic control subjects and 17 idiopathic OAB patients. The urine was analyzed by a multiplex panel screen for 12 chemokines, cytokines, growth factors, and soluble receptors using Luminex xMAP((R)) technology. Protein concentration values were normalized to the levels of creatinine. RESULTS: This analysis revealed a significant elevation of seven key proteins in the urine of OAB patients relative to controls (*P < 0.05). A greater than tenfold elevation was measured in OAB, relative to controls, in the levels of monocyte chemotactic protein-1 (MCP-1), soluble fraction of the CD40 ligand (sCD40L) in urine was obtained from OAB patients relative to controls. At least five fold elevations were detected in the levels of macrophage inflammatory protein (MIP-1beta), IL-12p70/p40, IL-5, epidermal growth factor (EGF), and growth-related oncogene GRO-alpha compared to controls. Significant threefold elevation was also noticed in the urine levels of sIL-2Ralpha, and IL-10 in the OAB group. The levels of the remaining proteins tested were not statistically significantly different from control values. CONCLUSIONS: The presence of elevated levels in urine of inflammatory biomarkers involved in inflammation and tissue repair suggests a role for inflammation in OAB, and may help in diagnosis and treatment of this disease.