The considerable knowlegde in insect physiology and endocrinology, which has accumulated during the last two decades allows the development of screening procedures for insecticides, which interfere with insect specific metabolic pathways or endocrine mechanisms. The suitability of this strategy is demonstrated by various insect growth regulators, which impair the endocrine regulation of the molting process like juvenile hormone analogues (JHA`s) or inhibit chitin synthesis, f. e. benzoylphenylureas, compounds which are already applied successfully since more than 20 years. Due to toxicological and environmental problems of most neurotoxic compounds and the development of resistance, the need for new insecticides is obvious. The efficiency of classical insecticide screening is decreasing, therefore new targets and strategies are necessary. Permanent cell lines, which have retained arthropod specific metabolic pathways or the hormonal regulation of metabolism or differentiation allow the development of screening procedures using insect specific targets.