Nucleolar organizer regions (NORs) were evaluated in 11 women with adenomyosis. The material, sampled during operations, was silver-stained using the technique of Ploton et al. and verified histopathologically. A hundred cell nuclei per slide were assessed. The examined variables comprised the number of argyrophylic nucleolar organizer regions (AgNORs) in the nucleus, the surface area of a single AgNOR and the position of the AgNORs in the cell nucleus, as well as the AgNORs' coefficient, which were all estimated under a microscope. The parameters were quantitatively assessed using computer image analysis software Multi-Scan Base V.8. Adenomyosis was found to be associated with a significant decrease (up to 60%) in the nuclear area, as well as with a marked reduction (up to 50% as compared with normal endometrium) in the number of AgNOR granules. The total area of AgNORs in the cell nucleus also decreased from 3.55 to 1.57 microm2. There were no significant differences in the number of granules per nucleus either in the control group or in the adenomyosis group. The AgNOR coefficient was found to be lower in adenomyosis compared to normal endometrium.