BRCA1 is a tumour suppressor, implicated in the hereditary predisposition to breast and ovarian cancer. Substantial data now exists to suggest a role for BRCA1 in transcriptional regulation. BRCA1 has been shown to interact with the RNA Pol-2 holoenzyme complex; to interact with multiple transcription factors such as p53 and c-Myc and play a role in chromatin remodelling. We have previously identified a range of BRCA1 transcriptional targets and linked these to specific cellular pathways regulated by BRCA1 such as interferon stimulation. Current research is focused on novel transcriptional mechanisms that underpin additional defined phenotypes associated with BRCA1 deficiency including sensitivity to DNA damage based chemotherapy and resistance to spindle poisons.