BACKGROUND: Gestational diabetes mellitus (GDM) constitutes a significant contributor to maternal and fetal morbidity, which is observed to be associated with future risks of offspring health. Nevertheless, it is essential to acknowledge that observational findings may be susceptible to residual confounding and bias. METHODS: To investigate the association of GDM with offspring health, a genome-wide genetic association study employing Mendelian Randomization (MR) is conducted between May 31 and November 30, 2023. The inverse-variance-weighted (IVW) is utilized in the primary analysis stage. The study data of the majority patients are European ancestry, which are sourced from the IEU open genome-wide association study project. RESULTS: Genetically predicted GDM is associated with an increased risk of various short- and long-term health problem in offspring. For fetal and neonatal conditions, GDM is linked to an elevated risk of preterm delivery [ odd ratio (OR) = 1.150, false discovery rate (FDR)-adjusted P CONCLUSIONS: The findings of this study provide genetic evidence supporting an association between GDM and higher risk of offspring diseases. This supports classification of GDM as risk factors for short- and long-term offspring health.