Insulin like-growth factor-1 (IGF-1) reflects hepatic synthetic function and plays a major role in the development and progression of various cancers. In the present study, we investigated whether baseline serum IGF-1 levels predict time-to-progression (TTP) and overall survival (OS) in hepatocellular carcinoma (HCC) patients treated with transarterial chemoembolization (TACE). A total of 155 consecutive treatment-naive patients with HCC who had undergone TACE as initial treatment were included from a prospective cohort. Baseline serum IGF-1 levels were analyzed with regard to their associations with disease progression and survival. During a median follow-up period of 41.8 months, patients with low IGF-1 levels showed significantly shorter TTP (median, 6.0 months; 95% confidence interval [CI], 4.5-7.6) than patients with high IGF-1 levels (median, 16.5 months; 95% CI, 4.9-28.1; p = 0.003). In the multivariate analysis, BCLC stage, serum vascular endothelial growth factorlevels, and IGF-1 levels were independent risk factors for disease progression. The hazard ratio (HR) of progression for each 10 ng/mL decrease in IGF-1 level was 1.072 (95% CI, 1.029-1.117; p = 0.001). Furthermore, together with tumor size, stage, and treatment response, IGF-1 levels were an independent predictor of poorer survival (for each 10 ng/mL decrease in IGF-1 level; HR, 1.057; 95% CI, 1.001-1.115; p = 0.045). In conclusion, low baseline IGF-1 levels independently correlated with shorter TTP and poorer OS in patients with HCC who underwent TACE.