OBJECTIVES: Estimate prevalence of and factors associated with prolonged clinical inertia among patients with Type 2 diabetes. METHODS: Using 2000-2005 automated clinical and pharmacy data, we identified an insured cohort of patients with diabetes at the time of oral monotherapy initiation (N=5082). Actuarial methods were used to estimate time to prolonged inertia (defined as 2 HbA1c values over 8% at least 90 days apart, not yet dispensed insulin with no medication change in the preceding 90 days). Among the subset facing prolonged inertia (N=1391), actuarial methods and Cox regression were used to estimate time to and factors associated with medication intensification (dose change, class change, or class addition) or control (HbA1c<7%). RESULTS: At inception, mean age was 60.1 years, 48% were female and 37% African American. Mean HbA1c was 8.8% and 97% were dispensed Sulfonylurea or Metformin. 8% of patients faced prolonged inertia within 1 year, 17% within 2 years, 24% within 3 years and 30% within 4 years. At the time of prolonged inertia, 55% remained on monotherapy, 25% were on combination oral therapy, and 20% had no medication on hand. Mean time to medication intensification/control was 7.3 months, with 27% having neither within 1 year. African American patients (hazard ratio=0.83, 95% CI=0.72-0.96), those with no anti-diabetic medication dispensing (0.66, 0.54-0.80) or combination oral therapy dispensing (0.83, 0.71-0.97) faced longer delays. Increased delays were also associated with each additional dollar of drug co-payment (0.95, 0.93-0.98). Shortened delays were associated with each additional HbA1c percent (1.11, 1.08-1.15) and each additional visit to emergency department (1.27, 1.02-1.59), primary care (1.80, 1.57-2.15) and endocrinology (1.95, 1.36-2.78). CONCLUSION: Patients with Type 2 diabetes facing prolonged inertia are at risk of further delays in appropriate management. Our findings suggest the presence of multi-level barriers to appropriate care. Increased contact with the health care system may mitigate risk.