Schizophrenia is a complex disorder associated with prominent negative consequences for patients and the society. Efficient diagnosis and treatment are thus of utmost importance. However, due to the lack of knowledge about the molecular mechanisms of the disease, it is currently impossible to predict the patients’ treatment response. To elucidate the molecular metabolic changes, which lead to the disease development, it is important to understand the genetic variability of genes leading to changes in metabolic and signal pathways. However, serotonin pathway as well as its regulation and genetics are extremely complex. There is currently no review which would enable the understanding of genetic variability of serotonin pathway in schizophrenia. In this thesis we have 1.) obtained the genes involved in the serotonin pathway, 2.) described their function in the serotonin pathway and 3.) discussed various genetic changes affecting the expression and function of their products. Accordingly, we have identified the topics that are poorly investigated. This will lead to better understanding of the serotonin pathway in schizophrenia and better study design based on the whole serotonin pathway regulome. Additionally, we have identified common problems occurring when associating genotype with phenotype and proposed possible solutions. This will facilitate the interpretation of complex results of association studies.