Based upon a group of 108 consecutive mammary carcinomas a comparative analysis of morphological parameters, DNA-ploidy and indicators of proliferation activity was made. A correlation between Bloom-Richardson scale, mitotic index, PCNA-labeling index and DNA-index was shown. The ploidy of mammary carcinomas was significantly related to the values of proliferative fraction, as well as to PCNA-labeling index. Among patients with axillary metastases the tumor size and the value of PCNA-labeling index were significantly higher than those in patients with negative lymph nodes.