Background: Acne vulgaris is a multifactorial skin disease. Several studies have shown that elevated levels of serum insulin-like growth factor-I (IGF-1) correlate with overproduction of sebum and acne. Recently an IGF-I (CA) polymorphism has been associated with acne vulgaris and a functional relationship between IGF-I (CA) polymorphism and circulating IGF-I levels in adults has been reported.Objectives: To investigate the presence of insulin-like growth factor-I (CA) polymorphism in Egyptian patients with acne vulgaris, estimate their IGF-I serum level and study the relation between IGF-I gene polymorphism and IGF-I serum level.Methods: The study included 50 acne patients and 50 healthy controls. The clinical severity of acne was assessed based on the Global Acne Grading System. Polymerase chain reaction was used to study the IGF-I (CA) polymorphic area. Enzyme linked immunosorbant assay was used to estimate serum IGF-I level.Results: Our study revealed a significant difference in the distribution of IGF-I (CA) polymorphism between patients and controls. The heterozygous (192-194) genotype was significantly encountered in the acne group while the homozygous (>194) genotype was significantly encountered in the control group. The homozygous (<192) genotype showed no significant difference between patients and controls. There was no significant effect of age and sex on the IGF-I (CA) polymorphism genotypes and it did not affect the severity of acne. Positive family history was significantly encountered among the heterozygous carriers (192-194). A significantly higher serum level of IGF-I in acne patients compared to controls was found. Although statistically not significant, serum IGF-I levels were higher in female acne patients compared to males. As regards severity of acne, we found that mild cases of acne had significantly higher serum level of IGF-I and an inverse yet statistically non-significant correlation existed between serum IGF-I level and GAG score. Our results revealed that homozygous carriers (<192 and >194) showed statistically significant higher mean levels than heterozygous carriers (192-194) with the highest level in the homozygous (>194) group. Conclusion: Our results suggest that IGF-I (CA) polymorphism may contribute to a predisposition to acne. Serum IGF-I level is significantly higher in acne patients than in control, however, it seems to be affected by several factors other than just being affected by the IGF-I (CA) gene polymorphism.