過重與肥胖已經被WHO認為是全球主要的公共健康議題，過重與肥胖除了會影響健康與其醫療與保險等經濟成本之外，還會經由影響生產力，進而影響勞動市場表現。過去討論體型和勞動市場關係的文獻大多在討論體型與就業或薪資之間的關係，較少著墨於其與職業類別的關係。 鑒此，本文主要討論體型對於職業類別的影響，分別以BMI、相對BMI與過重(含過胖)代表體型，過重係使用世界衛生組織(WHO)以BMI界定的標準，即定義BMI大於25的體型為過重以上群體，此外，相關文獻中使用之模型常假設就業傾向服從常態分配，有別於文獻，本文採用假設分佈較具彈性的樣本選擇兩階段半無母數模型(Seminonparametric two stage with sample selection model)以進行估計。 研究資料係取自美國2010年國民健康調查(NHIS)，因考量體型對職業類別影響可能存在內生性問題，本文使用Wooldridge (2010)中的Control Function approach處理內生性問題，使用睡眠不足虛擬變數當作工具變數。 結果顯示：體型會對較需要與人直接互動的服務類別職業有影響，男、女性BMI都對服務業有顯著影響關係。特別是過重體型對於服務業存在負面影響，分年齡層檢視可知：年輕過重女性對服務業有負向顯著影響，中年過重男性對服務業也有負向顯著影響，而老年過重的體型則對於服務業無顯著影響。關鍵字：就業、職業、身體質量指數、兩階段半無母數。 Overweight and obesity has been considered the worldwide major public health issues by WHO. Overweight and obesity will affect health, labor market outcomes and the economic costs. In the past, most labor market literature discussed the body size affecting employment and salary but less discussion on its relation with the occupational categories. This study, hence, examines the impact of body size on occupational categories. It defines the body size based on BMI, relative BMI, or overweight or not. According to WHO, overweight (and obesity) is defined as one if BMI is greater than 25; zero otherwise. In the related literature on the analysis of employment, it is frequently assumed that the tendence of being employed follows a normal distribution. This study, therefore, uses a flexible distribution assumption by using the two-stage sample selection semi-nonparametric model.Data come from the 2010 National Health Interview Survey (NHIS) of the U.S. In order to take the potential endogeneity of BMI into account, this thesis uses “the lack of sleep or not” as an instrumental variable by using Control Function approach. The results indicate that BMI is significantly related to occupations Especially, overweight has negative effect on being employed in services industry. After considering the age cohorts separately, it finds that overweight has significantly negative effect on being employed in services industry for young females. Overweight also has significantly negative effect on being employed in services industry for middle-aged males. However, overweight is insignificant for elderly males and females.