This study of 845 patients with type 2 diabetes was conducted in 12 primary care general practices in a geographically cohesive region in Germany. It showed that about a fifth of these patients with known diabetes had a HbA1c of 8% or over, and therefore are in need of better glycaemic control. Younger patients seem to be at special risk for high HbA1c values, and they should receive particular attention with respect to preventive measures for better glycaemic treatment.