The possible association of human growth hormone (hGH) and insulin (INS) gene regions with metabolic control in diabetes was investigated in 98 subjects with non-insulin-dependent diabetes mellitus (NIDDM); 54 control subjects from the same population were also studied. Two polymorphic restriction sites in the region of the hGH cluster (BGLIIA and BGLIIB) show significant association with both glycemic and hemoglobin A1c (HbA1c) levels. Mean values for plasma glucose and HbA1c show a maximum in the BGLIIA *1/*1 genotype and a minimum in the BGLIIA *2/*2 genotype. Mean values for plasma glucose and HbA1c show a maximum in the BGLIIB *1/*2 genotype. The BGLIIA*2/BGLIIB*1 haplotype shows a negative correlation with plasma glucose and HbA1c levels. Since the two markers are located in the area surrounding the hGH-V locus, the expression of this gene in NIDDM warrants further investigation.