Molecular and cell biology have revolutionized not only diagnosis, therapy and prevention of human diseases but have also greatly contributed to the understanding of their pathogenesis. Based on modern molecular and biochemical methods it is possible to identify on the one hand point mutations and single nucleotide polymorphisms. On the other hand, using high throughput array technologies, it is possible to analyze thousands of genes simultaneously, resulting in an individual gene or gene expression profile (signature). These data increasingly allow to define the individual risk for a given disease and to predict the individual prognosis of a disease as well as the efficacy of therapeutic strategies (personalized medicine). In this review recent advances of predictive medicine and its clinical relevance will be addressed.