Genome wide association studies have identified the islet-restricted zinc transporter ZnT8 (SLC30A8) as a likely player in the control of insulin secretion and the risk of developing type 2 diabetes. The author's laboratory and others have now developed knockout mouse models for the ZnT8 gene, and have studied the impact of the at-risk R325W polymorphism on the activity of this crucial islet zinc transporter. Whilst there are intriguing differences between the phenotypes of the animal models the new studies provide strong evidence that the polymorphism in the SLC30A8 gene identified by human genetic screens is causal for the increased disease risk. The new results also reinforce the view that this transporter represents an exciting therapeutic target for intervention in type 2 diabetes.