The value of two "cancer risk" assessment rules (one consisting of qualitative microscopical features and one consisting of morphometric characteristics) has been evaluated in 39 patients with hyperplasia of the endometrium. Of these, in seven (7139 = 18%) cancer was detected in the follow-up and 32 remained stable or became less abnormal. The results of the qualitative analysis were well in agreement with those published earlier. In none of the eight patients with simple hyperplasia cancer was detected, in contrast to five of the 11 patients (45%) with cytologic atypia and glandular complexity. Twenty patients showed cytologic atypicality in the absence of glandular complexity, or no atypicality but glandular complexity; in two (10%) of these patients cancer was detected later in the follow-up. The morphometric rule (consisting of volume percentage of stroma, log-normally transformed standard deviation of the shortest nuclear axis and outer surface density of the glands) results in a multivariate score. Nineteen patients had a score value above 0.6 and in none of them cancer was found. In contrast, in seven of the 20 patients (35%) with a score value below 0.6, cancer was detected. Regarding the question which of the techniques is more powerful, the specificity is better with the qualitative evaluations; the sensitivity is higher with the morphometric rule. An advantage of the morphometric rule is that only two groups (very low/very high risk) are discerned.