Reduced expression of the adhesion molecule E-cadherin has been associated with increased invasiveness and poorer survival in patients with bladder cancer. We have examined soluble E-cadherin (sE-cadherin) and total protein concentrations in urine from patients with bladder cancer (n = 34), non-neoplastic benign urological diseases (n = 14) and healthy controls (n = 21) to determine their diagnostic and prognostic significance. Soluble E-cadherin concentrations of the cancer group were significantly higher (P < 0.001) than those of the controls but the benign group was not significantly different from either the cancer group or the controls. When sE-cadherin concentrations were adjusted for creatinine, similar but more statistically significant results were obtained and the benign group was significantly elevated compared with the controls (P < 0.01). No differences were apparent between the invasive (pT1-4) and non-invasive (pTa) cancers. Urinary total protein concentrations in the cancer group were significantly higher than the controls (P < 0.001) and the benign group (P < 0.05) although no difference was seen between the benign group and patients with non-invasive (pTa) cancer or between the benign group and controls. When expressed as the protein/creatinine index, results were similar but more statistically significant and a significant difference was seen between invasive and non-invasive cancers (P < 0.01). Only the protein/creatinine index correlated significantly with stage of the tumour (P < 0.01). It is concluded that urinary sE-cadherin measurements are of no greater value than urinary total protein.