The main target of growing pest-resistant plants is to reduce crop losses due to insect pests and to reduce insecticide applications. A reduction in insecticide use in Switzerland is only possible for Bt-potatoes and oilseed rape expressing proteinase inhibitors; in Switzerland no insecticides are registered nor used against the corn borer. As the three main pests of the crops discussed (corn borer, Colorado potato beetle, pollen beetle) have already developed resistance against several insecticides in the lab, it is possible that transgenic pest-resistant crops will loose their efficiency in the long term. Several laboratory studies on side-effects of transgenic crops on non-target insects indicate negative impacts of the toxin-expressing plants. Such effects are not demonstrated so far in the few existing field studies. Final conclusions on this subject are not possible yet. Vertical gene transfer is possible from all three transgenic crops on non-transgenic varieties within the maximum distance of pollen dispersal. From the many plants (manly widespread weeds) closely related to oilseed rape, vertical gene transfer has only been observed on turnip (Brassica campestris).