This meta-analysis aimed to estimate the association between gestational diabetes mellitus (GDM) and occurrence of macrosomia for the first time among Iranian population.A systematic review was done of national and international databases. Lists of relevant articles were checked to increase sensitivity of the search reference. Also, access to unpublished articles and documents were accessed by negotiation with related individuals and research centers. These published epidemiological studies (cross-sectional, case-control and cohort studies) were used for comparisons to determine whether GDM was associated with macrosomia. Finally, the Mantel-Haenszel method and the fixed and random-effect models based on heterogeneity of the primary studies were used according to pool results and estimate the odds ratio of macrosomia in women with GDM.Of 1870 articles, thirty relevant articles were eligible for the current meta-analysis. Our findings showed that 335 of 2524 women with GDM had macrosomia while only 775 of 26,592 women without GDM had macrosomia. Using random-effect model, the pooled odds ratio (OR) relation between GDM and occurrence of macrosomia was estimated as of 5.49 (95% CI: 4.27-7.04). Subgroup analysis showed no difference regarding different study designs and definitions of macrosomia. There was no evidence of publication bias based on the result of Egger's test (β = 0.1,  = 0.70).This meta-analysis shows that GDM is directly associated with the risk of macrosomia in the Iranian population. This confirms the findings of previous studies in the wider scientific literature.