Obestatin is a recently discovered peptide produced in the stomach, which was originally described to suppress food intake and decrease body weight in experimental animals. We investigated fasting plasma obestatin levels in normal weight, obese and anorectic women and associations of plasma obestatin levels with anthropometric and hormonal parameters. Hormonal (obestatin, ghrelin, leptin, insulin) and anthropometric parameters and body composition were examined in 15 normal weight, 21 obese and 15 anorectic women. Fasting obestatin levels were significantly lower in obese than in normal weight and anorectic women, whereas ghrelin to obestatin ratio was increased in anorectic women. Compared to leptin, only minor differences in plasma obestatin levels were observed in women who greatly differed in the amount of fat stores. However, a negative correlation of fasting obestatin level with body fat indexes might suggest a certain role of obestatin in the regulation of energy homeostasis. A significant relationship between plasma obestatin and ghrelin levels, independent of anthropometric parameters, supports simultaneous secretion of both hormones from the common precursor. Lower plasma obestatin levels in obese women compared to normal weight and anorectic women as well as increased ghrelin to obestatin ratio in anorectic women might play a role in body weight regulation in these pathologies.