Glutamate, the major excitatory neurotransmitter in the brain, has an important role in mediating the effects of alcohol and the development of alcoholism. Among different glutamate receptors, kainate receptors and their role in alcoholism are so far the least explored. One of the genes for glutamate receptors that has been found to be associated with alcoholism is GRIK1 gene, encoding the GluR5 subunit of kainate receptors. Although research shows that certain polymorphisms in the GRIK1 gene significantly affect the activity of topiramate, a drug effective in the treatment of alcoholism, further studies are needed. The aim of the research is to investigate the association between rs2186305 polymorphism of GRIK1 gene and alcoholism in subjects of Croatian origin. The frequency of GRIK1 genotypes and alleles was compared between alcoholics and healthy subjects, divided according to gender and smoking status. Moreover, the distribution of genotypes and allele of polymorphism rs2186305 has been investigated in group of alcoholics subdivided according to age of onset of alcohol abuse, suicidal and aggressive behavior, as well as the type of alcoholism according to Cloninger classification. Haplotype analysis of the polymorphism rs2186305 in combination with polymorphism rs2832407 has been conducted in healthy individuals, as well as in subjects addicted to alcohol. The results should contribute to a better understanding of the role of the GRIK1 gene, encoding subunit GluR5 kainate glutamate receptors, in the development of alcoholism, as well as to the research of new potential targets for the therapy of this chronic disease.