Among subjects with severe sleep apnea (AHI > 30; n = 31; 53%), we observed lower ghrelin levels, especially in the second half of the night and in the morning (p5.00 = 0.0207; p7.00 = 0.0344); the presence of OSA had no effect on obestatin and leptin levels. Here, LEP is linked to obstructive sleep apnea syndrome.