The most researched candidate genes of psychiatric genetic association studies are the components of the monoamine neurotransmitter systems, out of which serotonin and dopamine transmitter systems gained particular attention due to their major role in regulating emotional functions and cognitive processes. The paper reviews association studies focusing on the polymorphisms of receptors, transporters and enzymes that belong to these two transmitter systems. Numerous studies demonstrated significant associations between serotonergic and dopaminergic polymorphisms and diagnostic categories, personality traits and cognitive functions, however, results of monoamine gene variants and psychological properties are often contradictory. The contradictions can partially be explained with relatively small sample sizes of earlier studies, heterogeneity of methods across the studies and our expanding knowledge of the function of polymorphisms. On the whole, however, it can be declared that psychogenetic research plays an important role in the development of personalized pharmacotherapy.