The review deals with the pathways of Bt corn (Zea mays L.) byproduct entry to the environment. Bt plants are genetically modified plants containing the genes of a gram-positive aerobic spore-forming bacterium Bacillus thuringiensis encoding &amp;#948;-endotoxins. Special attention was given to decomposition of corn detritus in fresh water and migration of Bt toxins to stream ecosystems. The results of field and laboratory experiments on the effect of Bt corn byproducts on stream detritophages are summarized.