Our aim was to investigate whether insulin sensitivity, leptin, androgen or estradiol levels are associated with disturbed GH response to clonidine in lean patients with polycystic ovary syndrome. Fourteen lean polycystic ovary syndrome patients, 11 ovulatory patients presenting idiopathic hirsutism and 10 non-hirsute, normal women with regular cycles paired for age and BMI were included in a cross-sectional study. Baseline hormonal and metabolic variables were assessed and analyzed in association with GH response to oral administration of 0.3 mg of clonidine. Delta GH was significantly higher in the PCOS group than in the IH and control groups (p = 0.014). The groups were similar in terms of body mass index, insulin, glucose, total and HDL cholesterol, triglycerides and estradiol levels. Free androgen index (r = 0. 454, p = 0.015) and leptin (r = 0.419, p = 0.023) were positively correlated with the homeostasis model assessment. The homeostasis model assessment was the only variable that significantly correlated with GH response to clonidine (r = 0.375, p = 0.029) (vs. estradiol, free androgen index, leptin and LH). Nonetheless, when the analysis was adjusted for leptin levels and free androgen index, the statistical significance of this correlation was lost. The increased GH secretion observed in our lean PCOS patients may be associated with slight changes in insulin sensitivity, even in the absence of clinical evidence of insulin resistance. This association seems to be modulated by leptin and androgen levels.