Context: NPY is an important central orexigenic hormone but little is known about its peripheral actions in human adipose tissue (AT) or its potential paracrine effects. Objective: To examine NPY’s role in adipose tissue (AT), specifically addressing NPY protein expression, the effect of NPY on adipokine secretion and the influence of insulin and rosiglitazone (RSG) on adipocyte-derived NPY in vitro. Methods: Ex vivo human AT was obtained from women undergoing elective surgery (Age:42.7±1.5years(mean±SE), BMI:26.2±0.7kg/m², n=38). Western blot analysis was used to determine NPY protein expression in AT depots. Abdominal subcutaneous (AbSc) adipocytes were isolated and treated with recombinant (rh) NPY, insulin and RSG. NPY and adipokine levels were measured by ELISA. Results: NPY was localized in human AT and adipocytes and confirmed by immunohistochemistry. Depot-specific NPY expression was noted as highest in AbSc AT (1.87±0.23ODU) compared with omental (Om:1.03±0.15ODU, p=0.029) or thigh AT (Th:1.0±0.29ODU, p=0.035). Insulin increased NPY secretion (control:0.22±0.024ng/mL; Ins1nM:0.26±0.05ng/mL*; Ins100nM:0.29±0.04ng/mL* and Ins1000nM:0.3±0.04ng/mL*; *p<0.05, n=13) but co-treatment of RSG(10nM) with insulin(100nM) had no effect on NPY secretion. Furthermore, adipocyte treatment with rhNPY down-regulated leptin secretion (Control: 6.99±0.89ng/ml; rhNPY1nmol/L:4.4±0.64ng/mL*; rhNPY10nmol/L:4.3±0.61ng/mL*, rhNPY100nmol/L:4.2±0.67ng/mL*; *p<0.05, n=10) but had no effect on adiponectin or TNF- secretion. Conclusion: NPY is expressed and secreted by human adipocytes. NPY secretion is stimulated by insulin but this increment was limited by co-treatment with RSG. NPY’s anti-lipolytic action may promote an increase in adipocyte size in hyperinsulinemic conditions. Adipose-derived NPY mediates reduction of leptin secretion and may have implications for central feedback of adiposity signals.