Le novaluron (20% WettablernPowder), is a recently developed benzoylurea insecticide which is considered asrnchitin synthesis inhibitor with excellent activity against mosquito larvae. Therncurrent study aimed to evaluate under laboratory conditions the potentialrnside-effects of novaluron on non-target shrimp, Palaemon adspersus Rathke,rn1837 (Decapoda, Palaemonidae). The compound was tested at two concentrationsrn(0.91 μg/L and 4.30 μg/L) corresponding respectively to LC50 and LC90rndetermined against fourth-instar larvae of Culiseta longiareolata (Diptera,rnCulicidae). Novaluron was added to the rearing seawater of newly-ecdysedrnadult shrimps of P. adspersus and exposed for 15 days, i.e. untill stagernD during the molting cycle. The weight of cuticles and their biochemicalrncomposition (chitin, proteins) were measured in peripheral integument by arngravimetric method. Under normal conditions, the weight of cuticle increase significantlyrnduring the period from the stage A untill the stage D. Novaluron-treatment wasrnfound to reduce the weight of cuticle at the stage B, C and D. The chitinrnpercentage, increase from stage A to stage C followed by a decrease at stage D.rnExposition of shrimps to novaluron resulted in a significant decrease of valuesrnat all molting stages with a dose-dependent manner. Lastly, the percentage ofrncuticular protein showed a decrease from stage B to stage D in controls.rnNovaluron can cause a significant increase in cuticular proteins. Therefore,rnthe overall data confirm the primary mode of action of novaluron to inhibitrnchitin biosynthesis.