Hyperglycaemia leads to increased formation and accumulation of advanced glycation end products, and these molecules play an important role in the development of micro- and macrovascular complications in diabetes. The formation of advanced glycation end products are complex reactions that take place both intra- and extracellularly. Advanced glycation end products affect gene regulation by binding to receptors, but can also modify proteins, DNA and lipids directly. The amount in serum and tissues depends upon several factors. The extent of hyperglycaemia is the main determining factor for levels of glycation products in the body, but the ability to break down and excrete these products in the urine is also important. The most effective way of preventing late complications in diabetes caused by glycation products is strict regulation of blood sugar levels. Drugs that inhibit advanced glycation end products could potentially be important in the prevention of late complications in diabetes, but this needs further investigation.