Aims: Coagulation activation is a recognized complication of cancer in which increased tissue factor (TF) is implicated. TF can be detected in urine (uTF). This study assesses uTF levels in benign and malignant urological disease and correlates the results with conventional markers of tumour progression. Methods: Using a simple and reproducible kinetic chromogenic assay, we determined uTF levels in controls (normal volunteers (n = 57) and patients with renal stones (n = 30)), benign and malignant bladder (n = 75) or prostate (n = 106) disease and in patients with or without recurrent bladder cancer (n = 30). Each benign disease group was stratified as inflammatory (cystitis or prostatitis) or non-inflammatory (negative cystoscopy following haematuria or benign prostatic hypertrophy). Results: The controls and the benign non-inflammatory results were indistinguishable. The malignant and inflammatory groups showed raised uTF levels over controls (P < 0.001 bladder and P < 0.01 prostate). The difference between malignant and benign inflammatory disease was only significant for the bladder group. uTF levels were significantly I related to histological tumour grading, prostate serum specific antigen, static bone scan images and recurrence status. Conclusions: uTF levels can distinguish, statistically but not without overlap, patients with malignancy from normal controls and benign non-inflammatory conditions. Discrimination between inflammatory and malignant disease has only been demonstrated in the bladder. uTF levels showed it significant association with markers of tumour progression or metastasis and may be useful in predicting bladder tumour recurrence. (C) 2000 Harcourt Publishers Ltd.