Use of predictive biomarkers plays a promising role in stratifying patients to a more effective medical treatment with less side effects. This review provides a brief overview in a Danish context of the potential of applying pharmacogenomics (PGx) including companion diagnostics (CDx) in daily clinical practice based on the current knowledge and regulation from the FDA and EMA, Summary of Product Characteristics (SPC), PharmGKB (pharmacogenomics knowledge resource providing clinical dosing guidelines) and partly promedicin.dk. Also, the barriers to more widespread use are being addressed.