BACKGROUND Circulating insulin-like growth factor (IGF)-1 and IGF-binding protein (IGFBP)-3 levels in the serum of Helicobacter pylori (H pylori)-infected patients were investigated. METHODS The study subjects consisted of 54 patients with H pylori infection, and the control subjects included 27 patients without H pylori infection. There was no statistical difference in the age and sex distributions between the study and control groups. Pretreatment serum levels of IGF-1 and IGFBP-3 were studied in all the subjects, including the healthy controls. H pylori eradication was achieved with a triple drug regimen for 2 weeks, and 1 month after this treatment, the serum levels of IGF-1 and IGFBP-3 were measured. The post-treatment H pylori status by a second gastroscopy, antral histopathology and urea breath testing was tested. RESULTS The pretreatment serum levels of IGF-1 and IGFBP-3 of the study and control groups were not found to be different (P > 0.05). H pylori treatment was successful in 42 patients in whom both serum IGF-1 and IGFBP-3 levels decreased with treatment, but the difference was only significant for the serum IGF-1 levels (P: 0.04). There was no change in the serum levels of IGF-1 and IGFBP-3 in the 27 patients with precancereous gastric lesions before and after successful H pylori eradication. CONCLUSIONS No supporting evidence of a major interaction between H pylori infection itself and H pylori-associated premalignant lesions with circulating IGFBP-3 levels could be shown. Nevertheless, successful eradication of this microorganism led to a statistically significant decrease in serum IGF-1 levels.