DNA parameters and a DNA status index were calculated in cases of noninvasive urothelial papillary carcinomas and apparently normal urothelium. DNA feature analysis included the measurement of basic parameters as well as those related to DNA deviation. Normal urothelium had a diploid content with a few values between 2c and 4c. The papillary lesions in the three grades showed a progressive decrease in diploid nuclei and steadily increasing percentages of tetraploid ones. One case of grade 1 papillary carcinoma and some of grade 2 showed a small proportion of aneuploid cells; the proportion quintupled in grade 3. The values of parameters related to DNA deviation increased progressively in the three grades, numerically expressing the shift from diploidy. The DNA status index is a multiparameter classification in which a single number, ranging from 0.5 to 3.7, expresses the degree of DNA deviation from a non-proliferating diploid population. The cases of normal urothelium and of grade 1 had the lowest values, from 0.5 to 1.9, whereas grade 3 cases had the highest, from 2.2 to 3.7. The index values of grade 2 cases were partly intermediate and partly in the range of the neighboring grades. The DNA status index has a prognostic significance. In fact, associated lesions and recurrences were only observed in cases with index values over 2.0.