Cytochrome P4502C8 (CYP2C8) is a significant member of CYP enzyme family and metabolizes about 20% of commonly prescribed drugs and endogenous compounds. Single nucleotide polymorphisms in CYP2C8 gene may change CYP2C8 enzyme activity and therefore may affect the adverse reactions and efficacy of drugs metabolized by this. The purpose of the current investigation was to detect the genotype and allele frequencies of CYP2C8*4 in a healthy Turkish population and also to compare our findings with the other populations. CYP2C8*4 polymorphism was analyzed by polymerase chain reaction-restriction fragment length method using DNA samples isolated from 109 healthy Turkish volunteers. The genotype frequencies were 95.4% for the homozygous wild-type, 4.6% for heterozygous and 0.0 % for homozygous variant. According to this, the frequencies of wild type and variant alleles were determined as 0.977 and 0.023, respectively. The genotype frequencies did not deviate from the Hardy-Weinberg equilibrium. Significant population differences were observed when the findings were compared with those of other populations. This is the first investigation to examine the frequencies of CYP2C8*4 polymorphism in Turkish population. The determination of CYP2C8*4 polymorphism may provide useful data about the pharmacokinetics, efficacy and/or toxicity of its substrates and predisposition to some diseases and may help to improve personalized therapy in the future and also contributes to epidemiological studies. [Med-Science 2020; 9(2.000): 314-9]