Increased heel pad thickness can be used as a marker of soft tissue enlargement in acromegalic patients. We aimed to investigate if concomittant hyperinsulinemia/and or diabetes secondary to insulin resistance in acromegaly contribute to the enlargement of heel pad. We compared heel pad thickness in 16 diabetic and 16 nondiabetic active acromegalic patients using X-ray images. All of the diabetics were well controlled with diet and/ or oral antidiabetic drugs. GH and IGF-1 were similar in both groups. Heel pad thickness did not differ between diabetic and nondiabetic acromegalic patients (21.93±3.54 vs 22.92±3.80 mm, P=0.489) and was not correlated with fasting blood glucose, insulin, GH and IGF-1. In conclusion, diabetes secondary to acromegaly did not affect soft tissue enlargement represented by heel pad thickness.