OBJECTIVE The aim of this trial was to evaluate the effect on insulin sensitivity and body composition of combination therapy with GH and IGF1 in adults with GH deficiency (GHD) and diabetes. METHODS A 6-month randomised placebo-controlled pilot study. Fourteen adults with GHD and type 2 diabetes were included. All received rhGH (0.15 mg/day for 1 month and 0.3 mg/day for 5 months) and were randomised to rhIGF1 (15 μg/kg per day for 1 month and 30 μg/kg per day for 5 months) or placebo. Insulin sensitivity was evaluated with euglycaemic hyperinsulinaemic clamp and body composition by computed tomography of abdominal and thigh fat, as well as bioimpedance. RESULTS Twelve patients completed the study. They were overweight and obese; at baseline, insulin sensitivity (M-value) was low. IGF1 and IGF1 SDS increased in both groups, with the highest increase in the GH and IGF1 group. Positive changes in M-value by +1.4 mg/kg per min, in subcutaneous abdominal fat by -60.5 ml and in fat-free mass by +4.4% were seen in the GH and IGF1 group. Corresponding values in the GH and placebo-treated group were -1.5 mg/kg per min, +23 ml and -0.04% respectively (P=0.02, P=0.04 and P=0.03 for delta values between groups). No safety issues occurred. CONCLUSIONS Combined GH and IGF1 treatment resulted in positive, but rather small effects, and might be a treatment option in a few selected patients.