Explaining individual differences in human cognition has been a prominent goal of psychological research during the last century. Converging lines of evidence from human and animal research have shown that these differences are under the influence of genetic factors. However, identifying the specific genes involved is not an easy task. The complexities of the human genome and of the definition of the concept of cognition itself are obvious reasons why understanding the genetics of cognitive abilities is so complicated. About 20,000 genes are thought to have an impact on the development and functionality of the brain and each and every one of these may in fact have an effect on information processing, and therefore on cognition. In addition, the concept of cognition itself is very broad and has often been the subject of intense debate. It is therefore important to provide a precise definition of the cognitive phenotype before analyzing the genetic influences acting on it. Furthermore, the genetics of cognition can be investigated by multiple approaches that can be applied not only to human, but also to animal research. An overview of these methods and some of the results obtained is provided in an attempt to highlight the multidisciplinary complexity of studying the genetic bases of human cognition. Furthermore, some directions for future studies are suggested, highlighting the importance of analyzing gene-environment interactions and avoiding deterministic approaches. WIREs Cogni Sci 2011 2 345-352 DOI: 10.1002/wcs.135 For further resources related to this article, please visit the WIREs website.