Several studies have cited economic hardships or poverty as the main reason for women’s entry into sex work in India. While this may be true, it is still a vague reason. For better understanding and to develop meaningful intervention, we need to dig deeper and find more specific reasons for women’s entry into sex work. In addition, while most studies conducted among sex workers in India rely on survey-based approaches to explore women’s reasons for entry into sex work, there have been no studies to date which have used cultural biography to examine how sex work becomes a livelihood option for women in Indian society. Based on the analysis of the 46 short-life portraits and three life-history interviews collected from ‘flying’ or mobile female sex workers over a period of 7 months (December 2009–July 2010) in Kolkata, India, this paper examines the socio-cultural and economic factors that influence women’s decisions to enter into sex work. This study found that women choose sex work vis-à-vis other employment opportunities because it provides them with more freedom and autonomy over their bodies, higher earnings, flexible hours of work, and much flexibility to manage their dual responsibilities of a nurturer and provider. Because of this complex structure of causation, HIV prevention programs must address the larger issues of workplace sexual harassment, minimum living wage and child day care policy to disincentivize women’s entry into the sex industry.