AIM: The purpose of this study was to investigate which factors determine the initiation of glucose-lowering therapy in patients with Type 2 diabetes mellitus in general practice and their future glycaemic control. METHODS: All incident Type 2 diabtic patients in the general practices in a Dutch middle-sized town from 1994 to 2000 were identified. Factors associated with initiation of glucose-lowering therapy were obtained from clinical files and examined by Cox’s regression analyses. Using anova,the associations between clinical characteristics at diagnosis and future glycaemic control were investigated. RESULTS: In total, 603 newly diagnosed patients with Type 2 diabetes mellitus were included in the study. In the first month following diagnosis, 319 (53%) started with oral therapy. One, two and three years after diagnosis of diabetes, the cumulative incidences were 71% (95% CI 66-73%), 75% (71-79%) and 81% (77-84%), respectively. Age, gender, body weight, blood pressure, history of cardiovascular disease or total serum cholesterol values were not associated with time to start of drug therapy. An increased plasma glucose level at diagnosis was strongly related to faster initiation of drug therapy and worse future glycaemic control. Immediateinitiation of glucose-lowering medication was not related to future glycaemic control. CONCLUSION: This study shows that the initial severity of diabetes, assessed by the degree of hyperglycaemia at time of diagnosis, is a major factor in determining the time to start of glucose-lowering drugs and the likelihood of achieving target levels of glycaemic control in the future, independent of glucose-lowering strategy. Therefore, patients with high glucose levels at diagnosis need close monitoring from thebeginning of their disease.