This invention relates to nanomedical technologies, namely to the fabrication of nanocarriers of drugs for antitumor chemotherapy. The technical result of the invention consists of increasing the efficiency of antitumor chemotherapy by increasing the activity of the cell absorption of nanocontainers loaded with an antitumor drug, avoiding of the nanocontainer toxicity for cells due to the use of dispersed boron nitride nanoparticles of 50-300 nm in diameter with a well-developed outer surface. The method of boron nitride nanoparticles fabrication for antitumor drug delivery to tumor cells includes synthesis of spherical boron nitride nanoparticles of 50-300 nm in diameter with a well-developed outer surface by chemical vapor deposition using ammonia reaction gas, argon transport gas and powder mixture composed of amorphous boron and oxidizing reactants.