The development of methods for rapid and effective isolation of proteins from Escherichia coli is of considerable interest for biotechnology. The ability of buffer solutions containing low concentrations of detergents and chaotropic agents to extract intracellular proteins of E. coli cells was studied. We have shown that the solutions containing Triton X-100 or sodium deoxycholate and the mixtures of these detergents with urea are the most effective for this purpose. During the extraction of proteins from bacterial cells under the conditions studied, the release of RNA into solution also occurs, while DNA mostly remains inside the cells. The proposed treatment does not break the bacterial cell walls; proteins probably are supposed to penetrate through the pores of the murein network. In efficiency, our buffer mixtures are comparable to the commercial reagent, CelLytic B, and can be used in different scale purification projects.