Waters of the Yenisei River, certain rivers and lakes of the Altai Territory, and effluents of some industrial factories in Krasnoyarsk were studied by luminous bacteria biotest Microbiosensor B17 677F. The lyophilized luminous bacteria Photobacterium phosphoreum from the IBSO collection were used to design this biotest. The bioluminescent test is based on bioluminescence quenching resulting from the action of water samples on luminous bacteria. The test results indicated locations and zones of impaired water quality. The heaviest pollution of water in the Yenisei River was recorded in the zones 0-116 km downstream from Krasnoyarsk (Krasnoyarsk and satellite towns). The effluents of most factories were found to be toxic. Underground and surface waters of some areas of the Altai Territory had different toxicity levels; there were deviations from the norm in most water samples taken from the different lakes and rivers. The data from this study show that the luminous bacteria biotest is simple and convenient, and that the results obtained are within acceptable levels of accuracy for the evaluation of the toxicity of effluent and river water. It takes no more than 30 min to do the biotest. It can be used in ecological monitoring like the Microtox toxicity test.