Epithelial ovarian cancers are typified by frequent genomic aberrations that have been difficult to unravel. Recently, high-resolution array technologies have provided the first glimpse of the remarkable complexity of these aberrations with some ovarian cancers containing hundreds of copy number breakpoints, micro-deletions and amplifications. Many of these alterations contain cancer-related genes suggesting that the majority is disease-associated and not just the product of random genomic instability. Future developments such as next-generation sequencing and integrated analysis of data from multiple array platforms on large numbers of samples are poised to revolutionise our understanding of this complex disease.