AIM: To study the association of serum insulin-like growth factor-I (IGF-I) with diabetic retinopathy. METHODS: Serum IGF-1 levels were measured in 25 pregnant diabetic patients and 25 pregnant non-diabetic patients who were matched for age, ethnicity, parity and period of gestation. Fundus examination was performed in both groups at 28, 32 and 36 weeks of gestation. RESULTS: The serum IGF-I level was significantly elevated in pregnant diabetics compared to pregnant non-diabetics (366±199μg/L vs 184±89μg/L, (P=0.0001) at 24 weeks, 535±251μg/L vs 356±89μg/L, (P=0.007) at 32 weeks and 404±166μg/L vs 264±113μg/L, (P=0.003) at 36 weeks of gestation). The pregnant diabetics with established diabetes had significantly higher IGF-1 level than gestational diabetes at 28, 32 and 36 weeks of gestation. The serum IGF-I level in pregnant diabetics with retinopathy was significantly higher than that in those without retinopathy at all periods of gestation. CONCLUSION: Increased serum IGF-1 in pregnancy may increase the risks for retinopathy.