Abstract: Objective To find out the differences in the changes of GH/IGF I axis between type 2 diabetes and type 1 diabetes using radioimmunoassay method.Methods Basic concentrations of serum GH and IGF I in 19 cases of type 1 diabetes and 98 cases of type 2 diabetes were evaluated. The clinical and laboratory items of type 2 diabetic patients were also measured for related factor analysis with serum IGF I concentrations. Results The serum levels of IGF I (191 5±14 1μg/L) in type 1 diabetic patients were significantly lower than those of the control (266 3±17 7μg/L,P<0 01), while the basic levels of serum GH (2 53±0 51μg/L) were significantly higher as compared with the control (1 36±0 27μg/L,P<0 05). In type 2 diabetes, the IGF I levels (126 1±3 2μg/L) were also significantly lower than those of the control (153 4±8 3μg/L,P<0 05), and they were negatively correlated with age (P<0 05) and HbA 1c (P<0 05), and positively correlated with blood pressure (P<0 05) and fasting serum insulin levels (P<0 01). The basic serum GH levels (0 60±0 11μg/L) of type 2 diabetic patients did not change significantly (P>0 05) as compared with control (0 74±0 07μg/L).Conclusion The changes of basic levels of serum GH and IGF I in patients with type 2 diabetes were different from that of type 1 diabetes, and this abnormal GH/IGF I axis maybe due to persistent elevated levels of patients’ blood glucose.