The focus of this work was to investigate the toxicity of different metal nanoparticles (gold nanoparticles [AuNPs], silver nanoparticles [AgNPs], titanium dioxide nanoparticles [TiO2NPs]) on brine shrimp Artemia salina. We investigated if nanoparticles could have an influence on hatching of cysts and on mortality of larvae. Larvae (also called nauplii) and cysts were exposed to NPs for 24 hr in artificial seawater on microplates. At the end of the test, we assessed the endpoint (immobility/death) for the larvae by a stereomicroscope. Nauplii that appeared completely motionless, were counted as dead, and the percentages of mortality were calculated for each treatment. Instead for the cysts, the percentages of not‐hatched nauplii for each concentration considered were calculated by counting the number of whole cysts. Currently, nanoparticles toxicity has been investigated in several research; in our study we highlighted …