Epidemiological and genetic studies on smoking behavior have been performed, and in this study the human serotonin 2A receptor (HTR2A) polymorphism was examined in 82 smoking behaviorists and 125 healthy controls. HTR2A consists of at least 14 subtypes, depression and anxiety occur due to agonists, and hallucination, fever heat, psychomotor excitement and other symptoms also occur. The polymorphism in HTR2A (102T/C, -1438A/G) was identified by means of the polymerase chain reaction followed by restriction fragment length polymorphism, and the Fagerstrom Test for Nicotine Dependence was used to determine the extent of smoking behavior. The results suggest that the HTR2A (102T/C, -1438G/A) polymorphism might not be associated with susceptibility to a risk factor for developing smoking behavior. Further studies are required to determine whether or not the novel serotonin receptor (5-HTR) polymorphism reflects the pathogenesis of smoking behavior.