Personalised medicine describes a more rational approach to treatment decision making for patients with cancer than existed in the past .It takes into account specific characteristics of the patient and their cancer including its genetic profile in an attempt to select the right drug for the right patient rather than a “one size fits all “ approach to treatment. Personalised treatment is particularly important in oncology and is already well established in the clinic, but is rapidly evolving and has changed entrenched treatment paradigms. The development of new technologies is allowing researchers to screen the whole genome, proteome, transcriptome and metabolone to identify biomarkers and it is likely that many of these biomarkers will find future clinical application. It is clearly not possible in 15 minutes to give a comprehensive overview of the current applications of personalised or precision medicine in the oncology clinic today or to discuss the many challenges ahead including tumour heterogeneity, the design of clinical trials in small patient subsets, development of companion diagnostics, measuring benefit of treatment, pathways to regulatory approval and societal cost to name just a few. There are many examples of how genomic alterations such as ERBB2 amplification and mutations in EGFR/ kRAS/B-raf/c-KIT/ALK/BRCA etc. etc. directly impact on treatment recommendations in the clinic today. Much of the research effort to date has been focussed on identifying and then targeting so called driver mutations and altered signal transduction pathways in a wide range of tumours. More recently, there has been increased attention on targeting other systems that influence cancer biology including DNA repair and immune checkpoints and systems that influence adverse events or side effects associated with therapy. Oncologists now have to learn to manage a whole new range of treatment related toxicities associated with targeted therapies which were never encountered with cytotoxic chemotherapy which cannot be ignored. I will discuss and provide examples of the current status of personalised cancer medicine in the clinic today and address some of the challenges ahead.