The one-stop shopping center is a familiar place for shoppers. The development of the one-stop shopping center in response to the needs and satisfactions of consumers is quite important to the companies goal and strategy. The purpose of thesis tries to investigate consumer's behavior by exploring spending habit and its determinants. The study has conducted a consumer survey in the one-stop shopping center in the Bangkok Metropolitan area and collected 1,000 samples from the choosen 14 one-stop shopping centers are Mahboonkrong Center, Futerpark Rangsit, Seacon Square, Central Plaza Lardprao, Central Plaza Ramindra, Central City Bangna, Fortune Town, Bangrak Shopping Center, World Trade Center, Silom Complex, The Mall Shopping Center BangKae, The Mall Shopping Center Bangkapi, The Mall Shopping Center Thapra and The Mall Shopping Center Knamwongwan. In the presumed consumers behaviour, spending per trip represent the consumer behavior for shopping in the one - stop shopping center.Hee,the consumer behavior is determined by socio-economic variable such as sex,martal status, age, education, level of income per month, number of persons going together, number of services, shopper attended hours that clients spend in the one - stop shopping center and number of services in the one - stop shopping center. According to the findings, the proportion of consumer spending had been segmended into the following categories: shopping goods, buying meals and attend the cinema, respectively. Given an economic and social structure, it can be deduced that tendency to shop is positively related with car ownership, particular during the afternoon weekends. The shopping frequency by the majority of shoppers can be notified as once a week approximately. On the average, shoppers spent four hours in shopping center. The shoppers prefers to shop at the one-stop shopping center if commuting is not more than thirty minutes in the vicinity of 5 kilometers around the center. The important factors which influence the consumer's spending habit are the degree of accessibility, products'variety and the one-stop type of shopping services are provided. The sensitivities analysis reveals that if the clients tend to be married, who have higher age profile age profile, education with a high level of disposable income, consumers tends to spend more. On the contrary, it is dramatically noted that longer hours spent in the one-stop shopping center,the less the consumer's spending will be. However, the one-stop shopping center is the place that gathers many different kind of services and entertainment within its building, while consumers do not shop for goods only, but they may also want to use any other services and entertainment in the one-stop shopping center.