The expression of the nm23-H1 gene has been suggested to have an inverse association with metastases in certain tumours. The aim of this study was to investigate the relationship of nm23-H1 immunohistochemical expression with pathological tumour variables and survival in a series of transitional cell carcinomas (TCCs) of the bladder. Formalin-fixed, paraffin-embedded archival tissue from 87 carcinomas (Ta-T1 45 cases) and T2-T4 (42 cases) was immunostained (Strept ABC/HRP) with the NDPK-A monoclonal antibody (NDPK-A) against nm23-H1 protein. The tumours had already been evaluated for immuno-expression of p53 protein. In addition, DNA analysis was performed by flow cytometry. Results were analysed using the linear trend in proportions test, the Fisher's exact test and multivariate analysis. Paradoxically, advanced tumour stage showed significant correlation with nm23-H1 immunopositivity in muscle invasive TCCs (P(t) = 0.01). Patients with nm23-H1 positive, muscle invasive TCCs had a worse prognosis at a level of suggestive statistical significance (PF = 0.08). In multivariate analysis, using a Cox's proportional hazards survival model with six variables, tumour grade, disease stage and synchronous p53 and nm23-H1 detection showed significant correlation with poor patient survival (P = 0.014, P = 0.049 and P = 0.05, respectively).