Morphonuclear analysis using a quantitative image analysis system has been demonstrated to be a potentially useful technique in the prognostic evaluation of bladder carcinoma. The integrated optical density parameter permits DNA content evaluation in addition to 15 other morphonuclear parameters. We assessed the reliability of morphonuclear analysis by image analysis and flow cytometry for 46 bladder carcinomas and 14 normal bladder specimens. Frozen sample material was obtained from endoscopic resection, radical cystectomy and from cadaveric donors. The grade and staging of the tumours according to the World Health Organization was as follows: 8 G1, 18 G2, 20 G3 and 28 T1, 7 T2, 7 T3, 4 T4. Quantitative image analysis was made on imprint smears stained by the Feulgen method. Simultaneously cell suspensions were obtained by mechanical dissociation and stained with propidium iodide for Flow cytometry analysis. There was a good agreement between quantitative image analysis and flow cytometry for DNA content measurement indicating that image analysis is a reliable method for the quantitation of DNA content (P = 0.001). Moreover we found a good correlation between five of the morphonuclear parameters: surface (P < 0.001), chromatin clumps distribution (P < 0.001), frequency of small (P < 0.001) to large chromatin clumps (P < 0.001) and the grade of bladder tumours. These results indicate that morphonuclear analysis may be a valuable method of quantitating DNA and morphonuclear parameters in a single analysis to provide information which may have some prognostic significance for patients with bladder carcinoma.