OBJECTIVES: Determined how treatment of type 2 diabetes with drug therapy mirrors the accepted published clinical guidelines (for example those provided by the American Association of Clinical Endocrinologists). This included both initial drug therapy as well as therapies added over time. METHODS: Catalina Health Resource receives data from a nationally representative sample of pharmacy chains, representing approximately 40% of all national retail prescription volume, and comprised of over 130 million unique patients. Data are captured daily from the pharmacies, are fully HIPAA compliant, longitudinal, and not projected. Patient cohort included all patients who initiated type 2 diabetes treatment January-March 2006. Look-back period was 180 days and look-forward period was through December 2008. RESULTS: Patient cohort consisted of 77,302 new type 2 diabetes patients. Metformin is the recommended initial therapy, but only 61% of patients were prescribed it as their initial therapy. The remaining patients began on a sulfonylurea (23%) or a thiazolidinedione (15%). 62% of patients who started on metformin did not add other drugs during the study, as compared to 48% of patients who started therapy on an SFU and 43% of patients who started therapy on a TZD. 1% of patients who started on metformin added/switched to basal insulin as their second drug, mean time to add/switch was 547 days. 3% of patients who started on an SFU added/switched to basal insulin as their second drug, mean time to switch was 541 days. CONCLUSIONS: Nearly 40% of type 2 diabetes patients did not initiate therapy in line with published guidelines. Patients who initiated therapy on metformin had the highest rate of remaining on monotherapy. Patients who initiated therapy with metformin also had a lower rate of switching to/adding basal insulin as their second drug than patients who initiated therapy on an SFU.