The ErbB tyrosine kinase receptor family comprises 4 receptors (HER1 [EGFR/ErbB1], HER2 [ErbB2], HER3 [ErbB3] and HER4 [ErbB4]), and at least 10 ligands. Pre-clinical and clinical studies have indicated that members of this family have important roles in breast cancer development and progression, and which leads to the concept of targeting ErbB receptors as a promising treatment strategy. Trastuzumab, an anti-HER2 antibody, provided the first definitive evidence for the clinical efficacy of targeting an ErbB receptor in patients with breast cancer. Over the past 5 years, much interest has been generated as a result of the development of orally-administered ErbB tyrosine kinase receptor inhibitors. Pre-clinical and early clinical studies with these agents are reviewed here.