Summary: Schizophrenia is a mental disorder which affects about 24 million people worldwide. It is caused by a complex interplay of genetic and environmental factors. It would be of value to find out which genes predispose to schizophrenia. For many years geneticists have attempted to figure out which genes are relevant, through linkage studies, association studies and genome wide association studies (GWAS). Several genes and loci have been identified to have a modest effect on schizophrenia, but no single gene or chromosomal locus has been proven to, on its own, be linked to schizophrenia. Through linkage studies, chromosomal regions have been found to possibly have consequences for the development of schizophrenia. Through candidate gene studies, some genes seem to be relevant in schizophrenia. Genome-wide association studies, among other findings, show genetic variation on MHC locus as a contributor to schizophrenia. A major problem has been the reproduction of positive results; typically one positive association study has been followed by negative analyses. A great challenge has been to clarify the reasons for this, and develop new study designs, also considering gene-gene and gene-environment interactions. In this paper I will present an overview of some of today’s genetic challenges in research on schizophrenia.