OBJECTIVES: The Israeli National Health Insurance Law stipulates a National List of Health Services that all residents are entitled to. In March 2008, two tyrosine kinase inhibitors (TKIs), sorafenib and sunitinib, were added to the formulary indicated and limited for first-line treatment of metastatic renal cell carcinoma (mRCC). Oncologists could prescribe only one TKI, and patients are not eligible to subsequently receive the other. After 15 months on the formulary, we compared oncologists' prescribing preferences, treatment duration (TD), and survival in patients with mRCC treated with sorafenib or sunitinib. METHODS: We used demographic and claims data from Clalit Health Services’ 3.5 million client computerized database to identify all mRCC patients treated with either sorafenib or sunitinib since March 2008. Mean and median TD and patient survival were calculated and compared using a Kaplan-Meir analysis. RESULTS: Through the end of May 2009, 134 patients received sunitinib as initial therapy for mRCC, 29 patients received sorafenib. The two groups had similar demographic characteristics: mean (SD) age was 66.2 (±12.8) for sunitinib patients and 69.4 (±10.7) for sorafenib patients (p=0.212). Approximately 63% of the subjects in each group were males. Mean TDs were 8.0 months (95% CI 6.8-9.0) and 5.7 months (95% CI 3.8-7.8) for sunitinib and sorafenib, respectively (p=0.071). Median TDs were 7.0 months (95% CI 4.4-9.6) and 3.0 months (95% CI 1.4-4.6) for sunitinib and sorafenib, respectively. Mean survival times were 11.3 months (95% CI 10.4-12.2) and 8.1 months (95% CI 6.1-10.1) for sunitinib and sorafenib patients, respectively (p=0.023). CONCLUSIONS: Our retrospective analysis suggests that Israeli oncologists strongly prefer prescribing sunitinib for first line treatment of mRCC. Mean and median TDs and survival were longer for patients treated with sunitinib. Future analyses must control for patient clinical characteristics, which may have been a major factor in treatment preferences, and might have influenced TD and survival.