Silicon dioxide nanowires (SiO2NWs) have been taken into account as a novel nanocarrier to improve bioavailability of therapeutic compounds. However, despite the ever-increasing utilization of these nanocarriers, much less attention has been paid to determine their in vivo toxicity. Indeed, this study was designed to evaluate acute toxicity of SiO2NWs in Artemia franciscana nauplii, as a biological model. To this end, the sensitivity range of A. franciscana nauplii was estimated at different concentrations of 0 (control), 1, 10, 50, 100, 150, and 200 mg L-1 SiO2NWs for 96 h based on ISO TS 20787. The outcomes exhibited that 96-h EC50 value of SiO2NWs was 122.167 mg L-1 for A. franciscana. Moreover, SiO2NWs at high concentrations increased the immobilization rate of A. franciscana nauplii. Therefore, SiO2NWs were not acutely toxic to A. franciscana nauplii according to the information provided by European Union legislation and European Union Council Directive 67/548/EEC of 27 June 1967. Given that this study just assessed the acute toxicity of SiO2NWs, however, further studies must be conducted to evaluate intra- and extra-cellular effects of such nanowires.