<p>Cancer is driven by acquired genetic aberrations that drive the cellular cancer phenotype. In addition, hereditary genetic risk factors play a central role explaining the large difference in cancer risk between different dog breeds. There has been a revolution within genetic research over the past decades facilitated by technological advances and reduced costs. We can use sequencing technologies to characterize genetic changes in cancer cells and identify markers to diagnose and differentiate cancers. In addition, these technologies can lead to the identification of druggable targets, leading to advancements within cancer therapy. This review describes some of the advances within oncogenetics in companion dogs and provides an overview of published genome wide association studies investigating predisposing genetic risk factors as well as studies investigating somatic cancer-driving mutations in dogs.</p>