Background/aims: We aimed to determine the distribution of cytochrome P450 2C19 (CYP2C19) genotype frequencies in Turkish patients with dyspepsia. Methods: CYP2C19 genotype was determined in 100 Turkish patients with dyspepsia. DNA of the patients was isolated from whole blood and genotypes were detected by specific probes in real-time polymerase chain reaction (PCR). Results: The frequencies of heterozygous CYP2C19*2 and CYP2C19*3 genotypes were 13% and 1% in dyspeptic patients, respectively. Homozygous mutant CYP2C19*2 was detected at a rate of only 1% in the study population, and homozygous mutant genotype of CYP2C19*3 was not found. The frequencies of homozygous CYP2C19*2 and CYP2C19*3 genotypes were 86% and 99% in dyspeptic Turkish patients, respectively. Conclusions: This is the first study investigating CYP2C19 polymorphism in dyspeptic Turkish patients. Our investigation revealed that the most common CYP2C19 genotype was wild type CYP2C19 in dyspeptic Turkish patients. Dyspeptic Turkish patients are extensive metabolizers for proton pump inhibitors. This finding might have impact on the clinical consequences for the treatment strategies in dyspepsia.