Background: The incidence of HER-2 over expression among Omani breast cancer patients was reported as 40% (higher than international published figures). Since 2002 a total of 76 patients with early and metastatic breast cancer received Trastuzumab, the results and incidence of developing brain metastasis during treatment are presented. Methods: Prospective, single arm, single centre experience. Patients with confirmed HER-2 positive (+++ by Herceptest, or FISH positive) breast cancer who received Trastuzumab (either as adjuvant or for metastatic disease) were included. Eligible patients were aged > 18, ECOG PS ≤ 2, LVEF >50% and with adequate renal & liver function and with no evidence of brain metastasis prior to starting treatment. Adjuvant Trastuzumab was received for 1 year following chemotherapy in early breast cancer cases or as a single agent or in combination with …