IGFs (Insulin like growth factors) are important regulators of pancreatic beta cell development, growth and maintenance. Mutations in the IGF genes have been found to be associated with diabetes mellitus, myocardial infarction obesity. These associations could result from changes in insulin secretion. We aimed to investigate IGF-1 gene polymorphism in obese patients with insulin resistance. We included 100 obese patients with insulin resistance 30 healthy subjects to study. At baseline examinations, antropometric measurements were done. Genomic DNA from the patients and controls were prepared. Thyroid function tests and serum IGFBP3 levels were similar between patients and controls whereas IGF, GH levels were significantly lower in obese patients. We categorized the IGF-1 (CA)19 polymorphism area into 3 groups as lower than 192 bp (group 1), 192-194 bp (group 2), and higher than 194 bp(group 3). Group 3 was more frequent in both obese and control groups. IGF-1 levels were also significantly lower in obese group (138.51 +/- 49.3) in than controls (218.14 +/- 69.15). IGF-1 levels were significantly lower in obese patients. The most frequent IGF-1 gen polymorphism allel is >194 bp in both obese insulin resistant patients and controls. IGF-1 levels and the other biochemical and hormonal parameters were similar in different genotype groups. The cause of lower IGF-1 levels in obese patients might be different from IGF-1 gene polymorphism and it may be insulin resistance.