Thechemicalplantprotectingprocessisoneofthemostimportantpollutingactivitiesintheagriculturalproduction.Theecosystemofagivenhabitatcanbecontaminatedsimultaneouslybysprayedpesticidesandotherxenobiotics,e.g.heavymetalsduetotheagriculturalactivitiesduringtheplantprotectingprocesses.Therefore,thechemicalloadcanbeoccurredasacomplexproblem,sothecombinedtoxiceffect,i.e.toxicinteractionofatleasttwosubstancescanbeexpectedandthecomponentscanmodifyeachother’seffect.Recently,theexaminationofthecombinationofheavymetalsandotherchemicalsgainedsignificantgroundinbothavian(Fejesetal.,2001;Kertész,2001)andmammalian(Institórisetal.,2001;Peczeetal.,2001)toxicologyresearchstudies.Furthermore,theinteractioneffectsareexaminednotonlyinthefieldofecotoxicology,butalsoinallotherareasthatdealwithhealthcareandchemicalsafetyissues(Oskarsson,1983;Danielssonetal.,1984;SpeijersandSpeijers,2004). Thedifferentagriculturalareasofferfoodsources,shelterandbreedingplacestowildbirds,thereforethesprayedpesticideandotherchemicalsubstancescancontaminatenotonlytheadults,buttheembryosdevelopinginegg,aswell.Theeggsofthewildbirdsmaybeexposedtodifferentchemicalsonthecultivatedlandsatthesametimeandtheirtoxiceffectsmaycauseembryomortalityanddevelopmentalanomalies. Teratologicaltestscarriedoutonavianembryosprovideusefuldataforenvironmentalprotectionandfacilitatethedevelopmentofenvironmental-friendlychemicalplantprotectiontechniques(Várnagyetal.,1996). Theaimofourstudywastodeterminethetoxiceffectandinteractionofcadmiumsulphateandachlorpyriphoscontaininginsecticide(CyrenEC)onchickenembryosafteradministrationofsinglecompoundsandsimultaneouslybyinjectiontechnique.