Background: The treatment landscape for metastatic renal cell carcinoma (mRCC) has changed in recent years, with several targeted therapies becoming available for 1st and 2nd line use. The rapidly evolving treatment landscape has left physicians with an abundance of choices for the treatment of mRCC patients. This study aimed to understand whether this has resulted in varying treatment patterns across US regions in 1st and 2nd line targeted therapy for mRCC. Methods: RCC patients who initiated 1st line targeted therapy with a vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFr) or mammalian target of rapamycin (mTOR) inhibitor between January 1, 2004 and June 30, 2011 were identified in the MarketScan database. First-line therapy was defined as the first claim in the database for a targeted therapy. One drug claim was sufficient to establish a line of therapy and a new line was defined as switching to another agent. Treatment patterns in the 1st and 2nd line settings were assessed in patients who initiated 2ndtherapy line after FDA approval of everolimus (Ev) (March 30, 2009) and stratified by geographic region. Results: Of the 6,524 patients included in the study, 1,298 (36%) received a 2nd line targeted therapy after March 30, 2009. Although all possible permutations of treatment sequences were observed, overall, sunitinib (Su) and temsirolimus (Te) combined made up 80% to 83% of the 1st line regimens across regions. The most common sequence was Su->Ev, observed in 18% of patients in the North Central US to 31% in the Northeast; Su->Te was the next most common sequence in all regions. Among patients who received 1st line temsirolimus, the majority initiated 2ndline on either bevacizumab (Be) (7%-12%) or Su (6%-10%) across regions. Conclusions: The most common treatment sequences across all regions were Su->Ev and Su->Te. Although a consistent pattern of sequential therapy emerged across regions, a wide range of on- and off-label strategies was observed outside of the predominant pattern of care. Furthermore, very few patients in this study received additional targeted therapy after 1st line. Further research is needed to identify factors influencing these treatment strategies.