As we demonstrated earlier, the adapting X-ray doses (3 and 10 cGy) induced movement of chromosome centromeric loci in G0-lymphocyte nuclei. In the present study we investigated the influence of X-rays with 3 and 10 cGy doses on the content of total, 18S and 45S rRNA in human G0-lymphocytes because it is known that the transcription products participate in nucleus organization. It was shown that 3 h after irradiation the content of both total and 18S RNA was significantly increased. The 3 cGy dose induced higher level of the rRNA than 10 cGy dose did in cells of some individuals. At the same time, the 45S RNA content was not changed significantly. This result may suggest that process of rRNA transcription and primary transcript (45S rRNA) processing have been completed during 3 h after irradiation. The data about an activation of rRNA synthesis were confirmed by cytological observation. Under 3 and 10 cGy doses both nuclei diameter and area of the Ag-stained granules were increased, depending on dose. These data also may be connected with an initiation of rRNA transcription because of correlation of Ag-painting with nucleolus activity. Thus, adapting X-ray doses induce displacement of chromosome loci in lymphocyte nuclei and activation of rRNA transcription. Further investigations are required for understanding of these phenomena interconnection.