This article reviews the literature concerning the most important aspects connected with origin, development, severity and control of crown gall, the neoplastic disease of many plant species. The disease creates a significant economic problem, particularly in nursery production of fruit trees and roses. Besides general information on the disease and its causal agent, the course of pathogenesis was described. The infection of plants is of an unique character and consists of transfer of the part of bacterial Ti plasmid into attacked plant cell and its incorporation with genome. This leads to the formation of tumorous tissue. Signalisation and communication system on a molecular level between pathogen and plant was pointed out. The crown gall occuring on roots restricts transport of water and nutrients into above-ground-parts of plant, reduces plant growth and sometimes causes its dead. From among many means of diseaese control described the biological method seems to be most promising, especially for stone fruits and roses. In some countries, including Poland, the commercial preparations based on K84 strain of A. radiobacter were developed.