This Mendelian randomization study assessed whether duration of mobile phone use is causally related to stroke outcomes using GWAS-derived SNP instruments. The inverse-variance weighted analysis reported a significant increased risk for large artery atherosclerosis (LAAS) with longer mobile phone use duration, while other stroke outcomes showed no significant associations. Sensitivity analyses (including MR-Egger and heterogeneity/asymmetry tests) were reported as suggesting the LAAS finding was robust.