The attention to metabolic syndrome has constantly risen over the years as the disease is leading to disability and premature death in an increasing number of affected people. Next to environmental factors, genes and gene variations have been considered to play a role in causation. Leptin and adiponectin, two adipocytokines, as well as their receptors, have been the focus of this thesis as they, together with their genetic variations, have been linked to metabolic syndrome features. Results of a novel approach (genome-wide association studies) have been collected and compared so that the impact of leptin and adiponectin could be demonstrated and explained.