Summary Sera from 40 patients with newly diagnosed bladder cancer (28 superficial tumours (pTa and pTI) and 12 muscle-invasive tumours) were assessed by enzyme-linked immunosorbent assay (ELISA) to determine the concentrations of soluble E-cadherin (sE-cadherin), soluble E-selectin (sE-selectin), soluble vascular cell adhesion molecule-I (sVCAM-1) and soluble intercellular adhesion molecule-I (sICAM-1). Corresponding frozen sections of primary tumour were analysed for E-cadherin expression using the monoclonal antibody, HECD-1 and standard immunohistochemistry. Patients with bladder cancer had significantly higher concentrations of sE-cadherin compared with a control group (P=0.017). No difference was found between the two groups with regard to sE-selectin (P=0.403), sVCAM-1 (P=0.942) and sICAM-1 (P=0.092). High levels of sE-cadherin were related to poor histological grade (P=0.009), number of superficial tumours at presentation (P= 0.008) and a positive 3 month check cytoscopy in superficial disease (P= 0.036). Abnormal Ecadherin expression was associated with increasing tumour stage (P = 0.009) and grade (P = 0.03). There was no correlation between high levels of soluble E-cadherin in sera and abnormal E-cadherin expression by the tumour (P= 0.077). Elevated levels of sE-cadherin are found in sera of patients with bladder cancer and correlate with known prognostic factors.