In this study, the relationship between the haplotypes consisting of single nucleotide polymorphisms (SNPs) of serotonin 2A receptor (5HT2AR) gene (HTR2A) 102T/C (rs6313) and -1438A/G (rs6311) and smoking behavior was studied among 101 smokers and 99 non-smokers. It was shown that the genotypic and allelic frequencies of these polymorphisms were not associated with the smoking behavior. However, according to haplotype analysis, higher haplotype 1 ((-1438G) G-(102)T) frequency was observed in smokers than in non-smokers (P < 0.05). Pairwise D' and gamma2 values between the two SNPs in this study were 0.916 and 0.805, respectively. The two SNPs thus showed strong linkage disequilibrium with each other. This study suggests that 5-HT2AR gene haplotype (G-T) may be related to smoking behavior.